It’s entirely possible. When you engage in violence, there’s a real risk of inflicting serious harm or killing someone. That does not mean you need to like or enjoy that. Some people do, some people eventually find a way to make peace with it for the sake of their own mental health, some people come to enjoy it, and some never do. The possibilities for the myriad of ways one can deal with or come to terms about the consequences or even prospect of violence are endless. It’s a part of where the internal conflicts of violence come from and the questions your asking have been asked by countless individuals over the generations.
The only good answer is this one: we all have to find it for ourselves.
For people who deal with potentially violent situations on a regular basis, the consequences are a constant concern. For themselves and the people they’re dealing with.
Realizing and weighing your actions against this is a cornerstone to writing characters who engage in violence in a mature way. With that in mind, there’s no real wrong way to write a character’s approach to violence. Potentially hypocritical approaches, but not wrong ones.
Everyone who deals with violence regularly will have slightly different outlooks on it. The best way to categorize this would be as a kind of personal philosophy. The trickiest part is simply making sure their philosophical approach to violence is internally consistent.
You could have a character who only resorts to violence as a last resort; will attempt to defuse any potential situation, and only resort to violence if someone else escalates to it first. They’re going to try to talk it out first, use their words, and remain calm instead of leaping into the action. They wait until the other person fully commits to an attack and then answers with violence of their own.
You could write a character who will preemptively engage in violence if they see no way to defuse a situation. This approach could be the same as above, or it could be based on them pre-empting simply by noticing events swinging toward violence in their environment. This is essentially the guy who hits the other with a beer bottle as he sees them going for a knife or gun. This one waits and attempts to defuse, but attacks before the other person can commit in an attempt to stop the fight before it begins.
You could write a character who responds to provocations, and engages in excessive brutality as a necessary evil. This could be the guy when passing by someone who yells, “hey your mother!” delivers to them either a solid punch to the face or even a crowbar. They are provoked, they escalate harder and faster than the other person can respond. Their logic is that excessive violence safeguards them by ensuring the other person can’t respond. This is possibly never, for any reason.
You could even write a character who goes out, tortures and kills people, presents themselves as a monster to scare others into line, and believes that killing is wrong, and no one else should engage in violence, because this is their burden or sacrifice or whatever. They’d be a hypocrite, but so long as you remembered that, and had your other characters calling them out over it, there’s nothing that will inherently make them a badly written character. A difficult to write character, but not impossible.
Someone can engage in activities they find distasteful, because they believe it is necessary. Violence is one possible example. Understanding that this can do dire things to other people, and have serious consequences doesn’t change the situations where it’s necessary.
It’s also possible that a character will engage in violence because they saw no other option, but have regrets and second thoughts after the fact. This is actually also fairly common in the real world. Just because you shot someone to save your life, doesn’t mean you’ll be automatically okay with that decision tomorrow.
Real world violence comes with a sickening sensation that it cannot be walked back afterwards. You can never undo the things you’ve done; only live with the aftermath.
A character who dislikes violence may make their decisions entirely on the aftermath and consequences, rather than a philosophical aversion. They may not want to engage in violence because the people around them will suffer, or because they know the consequences for intervening will be more severe than letting the current situation slide.
There’s probably a broader metaphor in there somewhere.