Torture is something the vast majority of people find abhorrent. However, many of those same people follow a god that promises eternal torture for countless people. How can a god do this yet still be considered merciful? This is a problem that needs more examination.
Eternity is a long time and is it overkill?
One obvious question is: Why torture for all eternity? Assuming torture is needed, it would seem logical that a merciful god would end if after minutes, days, years, centuries or at the most a few trillion years or so. Eternal torture makes a death sentence seem very mild and merciful indeed. It seems odd that a punishment which many people think goes too far for human standards would be incredibly soft by the standards of their merciful and loving god.
Now, followers of these religions will argue that horrible criminals, mass murderers and the like (people this god supposedly created) deserve to be punished. That may be, but even for the most horrible figures in history like Hitler or Stalin, is not all eternity going overboard? Imagine having a birds-eye view of someone like Hitler being tortured now. Would not even one of his victims think enough is enough after a few days, centuries or trillions of years?
What are the alternatives?
If some people need punishment, could not a god find better ways? Things like community service and other forms of punishment should be enough for some crimes like not believing in the right religion or any at all. Or, their souls could simply be dissolved. Assuming they have to be kept alive for the punishment, then why not some kind of prison just outside this heaven?
Most find punishment for the sake of punishment a very problematic concept for even a short time. To bring people back from the dead to punish them for all eternity , especially when nothing good can possibly come from it, really stretches the boundaries of ethics!
Not to mention the reasons and evidence given
Furthermore, according to many religious teachings, this torture is being dealt out simply over what religious ideology, if any, people followed in life! If it is important to this god that people follow a certain religion, why not give overwhelming evidence to support it and save so many people (many of whom lived good lives) from the most horrible fates? As is covered in divine proof, the evidence is far less than what any being with unlimited power and time could easily give.
Finally, as the test is primarily about thought crime, the worst mass murderers in history could be in heaven now if they accepted the right religion before they died while their victims could be suffering the most horrible torture.
All according to plan
On top of all of this, if this god is all-knowing, he should have known the fate of the people he was creating beforehand. Why create people knowing they will be sent for sadistic eternal torture? No life at all is surely better than one followed by the most horrible torture for all eternity!
Another problem with eternal tortures for failing at test is that the test is so arbitrary. What about the child who dies of some disease (created by this god) or is brutally murdered (while this god watches)? Does this child go to eternal torture (as many religious people once believed) or straight to heaven? If the child goes to heaven, then this child is skipping this test that some people are being eternally tortured for failing. Therefore, Hitler, Stalin and all the others condemned to eternal tortures now could instead be in heaven if they only had the fortune to die young.
Nobody has ever explained why a merciful and loving god would deal out the most horrible eternal torture, especially over a test that is so arbitrary. If there is an answer, it goes beyond human logic even though the test is for humans.