It's not a lie. "I don’t think stupid social media activity should ruin a kid’s life" does two things: characterizes endorsements of racism and eugenics policies as "stupid social media activity", and asserts that exposure of such activity should not lead to someone losing their job. The part about not rewarding journalists who "destroy" people does not exist in a vacuum away from his downplaying of Elez's abhorrent racial views. If journalists had revealed Elez, for example, was a secret left-wing antifa supporter on Bluesky, I think we can reasonably doubt Vance's reaction would have been the same.

Edit: Now that you've brought Vance's tweet into focus, it's also interesting that he does not think Elez is currently a "bad dude" when he's expressly stated a desire to normalize hatred against an entire ethnicity