Azraile:
I can't order other players around when no one is doing anything wrong.
You're kind of being vague on this, but as the GM you certainly
can order the players around. It's perfectly fine that if Carl has a problem with the way Rob's acting for you to ask Rob to tone it down a little because it's making Carl uncomfortable. In fact, if someone were making me uncomfortable in a game, that's exactly what I would expect you to do!
The thing is, you don't know your players deeply. You don't know the fully story on why something is upsetting them. You don't know whether or not it's something they want to talk out or deal with at all. There are certain topics that I'd go straight to the GM and request that it be retconned out or I'll leave. Granted, they're all borderline Content Restriction violations, but they exist.
More mildly, if it's not what the game was supposed to be about, why are you, as the GM, fostering that conflict? I'm a pretty conflict-averse person, and my characters tend to be the same. If something goes beyond my threshold for enjoyment, I'll come to you as the GM and ask you to fix it. When you start saying "well, Bob wants to have a big inter-character conflict with you, you have to talk it out with Bob", that's my cue to go. I'm not doing that. I signed up to fight aliens (or whatever), not to engage in a deep dive of Bob's personal issues with me.
Alternately, I've had characters walk out of games before because of other characters. My cleric shows up at the "meet the party" session only to find out one of the other PCs is a sloppy drunk that's offensive and abusive to her? There's the door over there and other adventures beckon. If I'm playing a character and one of the other PCs decides to lay into me for no reason I can discern, my character may well leave. Or shoot them in the face. Is that better than going to the GM and asking for a resolution? It certainly makes the game more exciting for the 2-3 posts that it lasts past that.