It is really interesting to me that you would choose (6:25) since you read in it that god veils the hearts of non believers against believing, basically condemning them to his hell without any chance of reprise theoretically, the exegesis for this aya is also revealing.
Actually, I hate to say, I never chose this verse (or 8:31) for the reason you ascribe; I chose both verses because of the similarities of language between what the polytheists in Makkah said ("These are nothing but tales of the ancients.") and what Nizar said ("...you still worship the same ancient myths..."). No more, no less.
However, since you bring up the topic ("basically condemning them to his hell without any chance of reprise theoretically"), I disagree with your assertion; I believe Muhammad Asad's exegesis is more on the mark:
Since it is God who has instituted all laws of nature - which, in their aggregate, are called sunnat Allah ("the way of God") - this "sealing" is attributed to Him: but it is obviously a consequence of man's free choice and not an act of "predestination". Similarly, the suffering which, in the life to come, is in store for those who during their life in this world have wilfully remained deaf and blind to the truth, is a natural consequence of their free choice -just as happiness in the life to come is the natural consequence of man's endeavour to attain to righteousness and inner illumination. Note 7 (Quran Ref: 2:7)
...that is to say, man's "going astray" is a consequence of his own attitudes and inclinations and not a result of an arbitrary "predestination" in the popular sense of this word ... In his commentary on the above verse, Zamakhshari stresses this aspect of free choice on the part of man and points out that "God does not cause anyone to go astray except one who, as He knows, will never attain to faith; and He does not guide anyone aright except one who, as He knows, will attain to faith. Hence, the [expression] 'causing to go astray' denotes [God's] leaving [one] alone (takhliyah) and depriving [him] of all favour, whereas [the expression] 'guidance' denotes [His] grant of fulfilment (tawfiq) and favour .... Thus, He does not forsake anyone except those who deserve to be forsaken, and does not bestow His favour upon anyone except those who deserve to be favoured." Commenting on the identical phrase occurring in 16:93, Zamakhshari states: "[God] forsakes him who, as He knows, will [consciously] choose to deny the truth and will persevere in this [denial]; and ... He bestows His favour upon him who, as He knows, will choose faith: which means that He makes the issue dependent on [man's] free choice (al-ikhtiyar), and thus on his deserving either [God's] favour or the withdrawal of [His] aid ... and does not make it dependent on compulsion [i.e., predestination], which would rule out [man's] deserving anything of the above." Note 4 (Quran Ref: 14:4)
In other words, non-believers are not "condemned to hell without any chance of reprise." They all have the chance throughout their lives to mend their ways if they will only take the opportunity. The question is, will they? The further they go down the path of unbelief the more likely they will not do so. As they follow along that false path their hearts become more and more veiled. And yet there is still hope (IMO). We are all tested, believer and non-believer; insha'allah, we may recognize the errors of our ways prior to death.
IT is not always the imitation in us that drives us to move further away from religion, sometimes it's knowledge that does that. History is full of examples where people of highly regarded religious knowledge move away from religion because of moral conflicts.
In which case I'd say that people are failing their tests. Knowledge doesn't equal conviction. Knowledge isn't the most important criterion. Perhaps you're familiar with this part of a hadith qudsi (#6)?
[Another] will be a man who has studied [religious] knowledge and has taught it and who used to recite the Quran. He will be brought and Allah will make known to his His favours and he will recognize them. [The Almighty] will say: And what did you do about them? He will say: I studied [religious] knowledge and I taught it and I recited the Quran for Your sake. He will say: You have lied - you did but study [religious] knowledge that it might be said [of you]: He is learned. And you recited the Quran that it might be said [of you]: He is a reciter. And so it was said. Then he will be ordered to be dragged along on his face until he is cast into Hell-fire.
Don't just rely upon your nafs to say, "Well, I'm smart enough in my knowledge of religion to say that this apparent conflict goes against my principles; therefore, religion is wrong and I'll become a non-believer." If your principles were in line with your religious knowledge you'd work your way through the moral conflict:
Whoever among you witnesses a bad thing, it is necessary for him to bring that to a halt with his hands, and if he does not have the potential for that; then he should stop him through his tongue, And if he does not have the ability to stop that with his tongue, then by his heart; he should think bad of this sin and that is the lowest level of Iman.
The reality that religion (abrahamic and otherwise with few exception) creates moral conflict in our current society and doesn't allow the space for it to be more encompassing of growing trends or realities. So the result is that people either create new sects with encompassing understand of their own religion or drop it all together into the ritualistic sphere ... others adhere strictly (usually causing conflict) and they should all co-exist.
The details of human life change over time; the nature of humanity hasn't. As I commented on a friend's blog:
Have we really changed? No.
You have left, O Hector, sorrow unutterable to your parents, and my own grief is greatest of all, for you did not stretch forth your arms and embrace me as you lay dying, nor say to me any words that might have lived with me in my tears night and day for evermore.” (Andromache, the wife of Hector, grieving over his death in The Iliad)
The Iliad is perhaps the world’s first novel-length story, with the text being written down - at the latest - by the 6th century BCE. I’ve always thought that if you can understand the grief of Andromache, then humanity hasn’t changed in at least the past 2500 years.
The Qur'an and Islam (indeed, one could argue all religions) are concerned about human nature. "Growing trends and realities" are irrelevant. Nothing has really changed except that people would rather follow their nafs by either creating sects or going into unbelief.
I leave you all with one question, would a person who leads a moral life and does his fair share of goodwill and is religious deserve to be incarcerated and tortured for an eternity in a place called hell because he picked the wrong god?
Allahu alim. Who are we to judge who goes to hell and who doesn't? Are you trying to set yourself up as judge of humanity? You've certainly made a start, setting up your own standards; the problem is, you don't know if your standards match His standards. Best I think to follow His, considering that yours is pure conjecture and He is all powerful.