If you can’t be utterly perfect and morally exemplary then don’t bother? That’s effectively what you’re saying?
Therefore no one bother recycling, taking the bus rather than car occasionally, choosing more local holidays or taking their own reusable bags. Because you’re not even touching the surface of the actual problem so DONT BOTHER.
where in fact, just doing your best, when you can, with what resources you have will always be a million times better than doing nothing.
Whilst those who profess to be morally superior (for many reasons not just vegetarians) and make a big show of it then go completely against the point and make choices which are totally counterproductive could be seen to be a bit silly, they are still making better choices than most.
I’ve been vegetarian over half of my life, there have been episodes where I’ve eaten meat occasionally and times that I’ve bought a leather bag. I don’t profess to be perfect or a saint or superior, I just don’t want to digest dead things. I’m just doing my best, with what I’ve got and how my life is at any given time.