The thing thats been keeping me away from converting
I was never religious, but recently I've been learning a lot about Islam and I've agreed with all of it except for the great flood. I while back I used to watch videos on school shooters, terrorists, and Nazis and I noticed a pattern in these people. All of them did what they did because they were either insane or thought what they were doing was good. Obviously what these people did was awful but I personally believe instead of executing them or throwing them into jail we should try to rehabilitate them so they can recognize why what they did was wrong and/or help them with their mental problems. So why wouldn't Allah help the people instead of drown them like what happened in the flood. I understand that he told Noah (I'm pretty sure he has a different name in the Quran but I don't remember what it is) to teach them why there ways are wrong, but that still doesn't seem like enough especially considering that Noah would probably not be able to talk to everyone and Noah's word would be misinterpreted or not heard by many people which goes against Surah Al-Isra 17:15 "They heard from the time they were young that a deceitful liar named Muhammad claimed to be a prophet. As far as I am concerned, such people are [excused] like those whom the call of Islam has not reached..." Unless that only refers to Muhammad, and isn't consistent with all messengers. The whole story doesn't make sense to me especially since Allah is supposed to be merciful and Almighty why wouldn't he do more to help instead of just killing everyone? Is there an important part of the story that I'm missing?
Ps: I'm not trying to come with any hate or trying to get you to convert it's just that I'm confused and curious.