Hm, that's a tough case. I can understand your frustration and I would totally be making the same post if someone expropriated my community like that. Seeing it from a distant third person perspective, I can recognize that the admin however acted based on their truly held beliefs that the act promoted is akin to animal abuse (regardless of how feasible food supplements are, as they clarified later). So if one has such a strongly-held belief, it is understandable that they would take direct action like that.
That said, I think the admin is beholden to act less rashly in a decision around a conflict that ultimately doesn't have an immediate/urgent impact on anyone. They could have contacted the mods and explained their values do not match lemmy.world ones and arranged for a graceful community migration, rather than a hostile takeover.
Bad showing from the l.w admins, they were power trippin'.