That's just convenient defeatism. People are part of societies and are sensitive to choices others make. It does not save the sharks if you stop eating shark fin soup. But when there was a campaign against shark fin soup in China, and people actually chose to eat less of it, then that does have an impact on the shark population. Things can change surprisingly fast. It's just a drop in the bucket, but we're several billion people dripping into it. The collective impact of significantly reducing animal product consumption is important enough to try for it.
In general, drop the "this is a nonsense solution, we should do this other thing instead". We need to do all the things to survive this. Focus on making others with the same goal stronger, convincing them to do this other thing too, instead of ridiculing their efforts.
It's a laughing stock here in Belgium