There may be fallacies in there that I haven't spotted and there is certainly subjectivism and relativism to a degree, but there is no whataboutism or true Scotsman.
Lex as a character has gone through this same cycle a few times in both the comics and the animated series, he's the big had one day and a reluctant team member the next.
Laundering mass murderers is also common. That you don't approve is clear.
I wasnt trying to say a team up was a good story, only that it was possible to make it narratively feasible with the given personality we've seen so far.