Someone who exclusively ate meat for some reason who moved to chicken would have a greater impact than someone who exclusively ate chicken and went vegan.
But that first person could have an even bigger environmental impact by becoming Vegan instead of only eating chicken.
I’d disagree about that being the worst case scenario.
When I used to use Arch and asked a question on the Arch forum, they removed my post because they saw I was using Pamac so they assumed I was actually on Manjaro. They didn’t ask me if I’m using Manjaro or anything, they just assumed I was and removed it.
I reposted the question and clarified that I was using Arch, but that got removed again due to it being a duplicate of a removed question.
I made a meta post about what I should be doing in order to not get my posts removed and that got removed as well, though I don’t remember the reason they gave for that.
That was the last time I posted on the Arch forum and shortly after, I switched to Void Linux.