Do you believe that Allah will put sinners into a place of everlasting pain? The answer is yes or no. So what is your answer?
The answer is "Yes" because after all warning they still decided not to believe. If a law in our country can decide to punish the people who do wrong, Allah has every right to punish His own creation who decided to disobey Him.
What satisfaction does Allah get from inflicting this torture upon lesser beings than itself? In other words, what purpose does it serve Allah to be the inflictor of such agony? So far, you have avoided answering this question.
Allah is the Most Merciful, Most Beneficent, Oft-Forgiving. He doesn't wish to punish anybody. We are His creation. Why should He punish His own creation? The simple condition is that we Must believe in Him. We must worship ONLY HIM and HIM alone. He alone deserves worship. He is the sole Creator, Sustainer and Ruler of all the worlds He has created. He has no off-spring, no parents and no partner.
If some one believes in Him like this and believes in the FIVE pillars of Islam, he is expected to be forgiven provided he sincerely repents. Tears of repentance and remorse wash away sins and disobedience.
I am unaware of any circumstance in which an Atheist, Polytheist, or non-believer of any variety can enter Paradise. Hell in Islam is very similar to hell in Christianity and promotes the worst kinds of pain and torture.
Additionally, believers (Muslims, Christians, and Jews) who commit sins and do not seek clemency or perform repentance are also subject to being thrown in the hellfire with the others. However, these groups have the opportunity to "work off their sins" and have a possibility of escaping eternal torture.
Why should the Most Merciful get pleasure from punishing His creation? Doesn't Allah opens the door to repentance all the way to our last breath? Will a sadist give the opportunity to repent and receive mercy? Fortunately, Allah is not a sadist. Believers or nonbelievers get equal portion of Allah's mercy in life and both have free choice.
Also, since there will be no future scenario in which the sinner will be able to apply his/her newly learned lesson, such a punishment cannot be for the purpose of teaching the sinner a lesson. Therefore, Allah will be inflicting pain and agony because he desires it. What does this tell you about Allah?
You need to understand the purpose of your life in this world. Quran clearly says the purpose of this life is to test who among us will obey Allah. Believers will have paradise and non-believers will go to hell because of the choices they made in this world. In both cases, the life is eternal. Quran has very clear description of hell and after reading that if you still want to take your chances, that is up to you. Quran also says that people is hell will ask to be send back to this world so that they can do what Allah asked them to do but we only had one life to live in this world. Your only chance is now and don't tell me you have never heard about Quran or Islam or Allah. You did but chose not to believe.
If you refuse to believe, it's okay. No one judges you in this world. It's simple, you read, listen, and understand the sentence.
You already understand that you'll be punished for being like that. But then, you speak ill and make fun Quran and Allah. It's okay, for you and your atheist group and community. Only the Owner of later life can judge you fairly in this case and there is no one to be blamed but you and I because of the choices we made in this world.
You can deny everything but remember, your death is imminent and no one has ever escaped death (another sign for us to reflect only if we believe in life after death). You may die today, tomorrow, next year, next 10 years, etc. Those times are very close if you think. Don't ever make assumptions that after death is a zero space if you're not dead yet. It's not valid.