Let's try and find a Steel Man argument for this. Lets say...

She's been arrested for murder, and the cop who slaps her is the father of the victim. And he slaps her in response to her saying she'll murder someone else in his family. Oh, and for good measure, let's say the woman was a Nazi. I love Nazis getting punched.

That's a cartoonishly large motivation to slap the hell out of someone.

But, it's still not okay. Abuse of power is abuse of power. The power is the important dynamic here. Sure, this time it's a Nazi murderer. We don't like Nazis or murder. What happens when the people who decide abuse of power is okay aren't aligned with my views? What happens when they don't like trans people? Or people of color? Or you, individually and specifically?

This is not reactionary, it's fundamentally antithetical to a safe and free society.