For sure. And I don't mean to paint all anarchists with the same brush, since there are genuine anarchists as well as people who use the label anarchist and who even believe themselves to be anarchists, but who I think we would all here would agree are just radlibs at best. But even drawing on my own experience as my leftism developed (which it still is), it wasn't like a conscious "I want to impress liberals" thought process, but more like wanting people to know that I was aware of the "evils of authoritarianism" and that being a leftist and anticapitalist didn't require a submission to "authoritarian" doctrine. I imagine I'm not the only one who felt that way, and even though I know better now, I can still see it sometimes in other people who call themselves anarchists, people who correctly recognize liberals as the common enemy of all leftists, but who still are careful to avoid being associated with "tankies."
Well, a "dunk tank" is a thing that is still done at carnivals, fairs, and the like even today. It does have exceptionally disgusting racist origins even though most people don't know about that (this is itself a ridiculously common phenomenon in the US: seemingly benign things with racist origins). I think you're right that the name for it here was derived mostly from the fact that we're dunking on bad things, and "dunking" on something that way, as a term, has its origins in basketball. But the play-on-words with the carnival thing was intentional. Innocent of course, but still intentionally a reference to the carnival dunk tanks as a kind of pun playing with the newer slang from basketball dunking. So as a name for a comm, it's about both, if that makes sense. At least that's my understanding.