Funny, that's what I thought when I saw your thread title. Surely no one could be that ridiculous and ignorant in 2020 to be claiming that - if anyone - it is meat consumers, rather than meat producers, that are destroying the planet. Someone even helpfully pointed out that food transportation (though it depends on the specific food) has an insignificant impact on total greenhouse gas emissions, and I'm sure we can agree that the actual act of putting some meat into your mouth has a low impact as well, therefor almost all the impact is incurred at production.
As for faddish, there are many more ex-vegans than vegans, about 80% or so of vegans moves on to a different diet later. That's a sign of a fad diet. But calling it a fad diet was mostly an experiment to see how you would respond if it were your diet which was randomly "attacked." I obviously couldn't actually create a "Vegans are destroying class consciousness" thread anymore.