It's fine for Superman to be angry, it's quite another to nearly murder someone when you have the powers of a god and your name is Superman, and Superman who already controversial after Man of Steel. Context, Lex is a fragile human with mental problems, and Superman is supposed to be the adult in the room we should hold him up to higher standards than Lex Luthor. Personally, I don't like my Superman to be like enforcers from the mob. If Superman acted more like when Doomsday was around this wouldn't be a negative, that's how he's supposed to act. That doesn't erase the fact he nearly killed Lex because Clark is too stupid to learn how to control his emotions. As Superman this is an incredible responsibility whenever he uses his powers, he uses them wrong he'll kill people. In Smallville Clark this as a teenager before he went off to Metropolis, and that was a jock Superman. This is what I'd expect from a teenager with super powers with bad impulse control, not a full grown man who's been Superman for a length of time.
People see what they want to see, alright.It's enough to make a person pick up drinking, am I right?