What does that even entail though, you cant exactly force things to objectively matter if they don’t already, there’s no mechanism by which we could influence that. If you just assert values that you hold personally, you’ve merely created subjective meaning and done nothing relevant to nihilism’s truth value. Meanwhile If nihilism turns out to be objectively false, then you can’t fight it because it wouldnt even exist to fight. You can fight nihilists I guess, but then you’re in the generally disliked position of fighting people based on a belief of theirs that does not require them cause any harm to you or anyone else, because it doesn’t require anything at all.

Its about as bizarre a call to action as declaring that you dislike some branch of math and want people to help you fight it.