Well, it's not necessarily convincing because you're the one who brought up Tiananmen Square. Those protests could be bougie liberal protests and "tankies" could be crushing socialist dissent at the same time, because no one prior to you brought up that specific incident. And there definitely is a history of leftist infighting, and considering the relatively greater success of "tankies" than anarchists as far as building large-scale societal movements, the "tankie" side of things does historically tend to come out on top of said leftist infighting.