Here's my burbling-into-the-void take:
Gargron's attitudes make sense in light of the techbro axiom "Bigger is Better; Growth is Good."
Every time his ideas come under fire, his first protest is "but this will help Mastodon grow!"
grow, grow, grow. bigger, bigger, bigger.
It's the same thing that underpins most social media platforms' toxicity issues. More users, more "engagement", is always privileged over other concerns.