MainBrain,
Be careful when making such wide-sweeping statements, they are seldom true, as in this case: the Catholic religion certainly does not teach that all others are going to hell.
The Catechism of the Catholic Church covers this in paragraphs 836-848 but I will quote a bit of it here:
842 The Church’s bond with non-Christian religions is in the first place the common origin and end of the human race:
All nations form but one community. This is so because all stem from the one stock which God created to people the entire earth, and also because all share a common destiny, namely God. His providence, evident goodness, and saving designs extend to all against the day when the elect are gathered together in the holy city…
843 The Catholic Church recognizes in other religions that search, among shadows and images, for the God who is unknown yet near since he gives life and breath and all things and wants all men to be saved. Thus, the Church considers all goodness and truth found in these religions as “a preparation for the Gospel and given by him who enlightens all men that they may at length have life.”
847 This affirmation is not aimed at those who, through no fault of their own, do not know Christ and his Church:
Those who, through no fault of their own, do not know the Gospel of Christ or his Church, but who nevertheless seek God with a sincere heart, and, moved by grace, try in their actions to do his will as they know it through the dictates of their conscience—those too may achieve eternal salvation.
The Catholic Church does not, in fact, teach that anyone specifically is damned to hell, not Judas, not Hitler, not Muslims, Baptists, agnostics, or atheists.