Its because they literally cant even comprehend anything outside of their black and white world view. Their entire thought process is: "I on blue team. Blue team good. Red team bad. Do everything to beat red team. RED TEAM BAD. DESTROY RED TEAM."
You can try explaining how this is horrific government overreach that can (and will) be used on them, only to get back a vapid confused look replying "but they told us this is only to be used on bad man, why would they turn on good man like me?".
Its both disgusting but also kind of amusing watching the so call left cheer for near infinite escalation from the government, but the second a protestor so much as tosses a snowball at police its all gritting teeth, fist slams, and screaming about "SEE THEY ARE VIOLENT! THEY NEED TO DEPLOY TACTICAL NUKES!!! KILL THEM ALL!" despite being the ones saying "protest are the voices of the unheard", and shit.