You are right, Hamas are to blame for the atrocities in Gaza, Hamas are to be blamed for the civilian casualties in Gaza, Hamas are to be blamed for the killings of innocent Gazan kids.
Yahya Sinwar wasn't called, the butcher of Khan Younis by Palestinian civilians for no reason:
https://www.ynetnews.com/article/bkfvcggxje
https://www.hindustantimes.com/world-news/who-was-yahya-sinwar-the-butcher-of-khan-younis-101729177623829.html