If it weren't for the fact that these are the smart, mangaverse senshi, I would say they did something incredibly stupid (like trying to purify Chen and Ran. Or dust Yukari). But they've been in enough loops to learn that "shoot first, ask questions never" is a bad idea, so that option is out.
Ugh, I hate seeing this. Even the anime senshi aren't that stupid. They don't fight because their opponents because they are different. They fight because their opponents attacked their friends and 90% of the time if their friend wasn't turned into a monster, something was stolen from them that's necessary for the person to live (Star Seed, Pure Heart, life-energy, Dream Mirror). Monsters did actually kill if they had enough time to drain enough energy. The senshi always interfered before they could.
Not to mention nearly all the villains have done something to cross the moral event horizon right in front of them which of course drives them to kill this person as quickly as possible.
Senshi are only willing to fight people if they're endangering innocent people. They don't really give a crap what you do as long as you're not doing that.