Just remember, the morals of someone making an argument have no bearing on whether an argument is sound.
If the purpose of every argument is to prevail, then sure, invoking morals in any discussion can seem like a tactic. Moral hypocrisy can be particularly exhausting.
If the invocation of morals is always evidence of manipulation, though, then any ethical position can be easily dismissed.
Moral hypocrisy is cynical. But that doesn’t erase the value of morals and ethics. Morality, sincerity, and rhetorical effectiveness are still very different things
If you believe in karmic justice, someone who lacked sufficient morals should just lose an argument even if they are now trying to use morals to put forward a sound argument.
You cannot use a moral high ground unless you’ve earned that high ground through your past behavior.