And who are you to judge, exactly?
Silly. We all make moral decisions and moral judgments constantly.
The two meanings of 'judgement' get mixed up. Judging someone in the Bible refers to condemning them beyond redemption, and often to death, for sin. In contemporary language, 'judge' is used more loosely to refer to moral evaluation. You are right that moral evaluation is legitimate and good. After all, you have to morally evaluate sin in order to forgive it. But the question is whether you are doing so within a paradigm of love and forgiveness or hate and condemnation.
Do you assume superiority?
Sometimes, sure. Again, these are questions we all entertain. I'd assume that your moral behavior is superior to Hitler's and I'd guess you think so as well. I'll wager you believe that christianity is the one true faith, that is, you believe it superior. Or do you hold that there is no way one might insist that christian beliefs/ideas can be held superior to satanism? Or Jainism? Or atheism?
Good is obviously superior to evil, but we are all sinners and so it is arrogant to assume superiority instead of staying humble. Just because Hitler's sins might have been worse than yours, doesn't make you a good person for feeling superior to him. What makes you good is when you humble yourself to acknowledge that we all struggle with sin, including yourself. The goal should be to get better and make things better, not to take pride in superiority to others.
Why don't you forgive and love?
Tell me about your love for Islamists.
Islam literally means submission to God. Through Christ we are all forgiven and redeemed, if we can believe. But God's love is powerful enough to motivate people to serve Him as well, and I think this is what motivated Mohammed in his prophecies and what motivates true Muslims to honor and serve God.
As for all this terrorism done in the name of Islam, I'm not so sure that's actually religiously motivated or if it is secular politics masquerading in the guise of religion. I can see how arguments both ways work. E.g. if you truly believe some Satanic force in the world needs to be fought, isn't it right to stand up to it militarily? But on the other hand, people could be perpetrating the socialist politics of manipulation through killing and torture and doing it in the name of religion to demonize religion in the process. Those are both possibilities.
Do you seek to help others or destroy them for the sins you judge them for?
Depends on the sins, of course. Depends on severity of the "evil" involved and whether those "sins" are on-going or being planned. Would I destroy an active shooter in a mall if I could bash his head in with a baseball bat? Of course. But if you are suggesting there is any chance of christianity (or any major faith) being "destroyed", then you'd be a paranoid fool.
It's more a question of your general philosophical attitude toward sin as something to be forgiven in order to redeem sinners or whether you see sin as an excuse to beat people down and otherwise destroy them. In other words, do you truly believe in salvation and redemption?