"Stalin did nothing wrong, USSR looked cool" is a quickie that requires no work or long acculturation.
The reemergence of tankies involved people completely disconnected and unrelated to prior tankies.
Anarchism was simply inaccessible by comparison.
There was simply no recruitment machinery for randos who wanted to quickly join, learn shit, and gain standing via the internet.
These folks are *also* our fault because they usually had a very anemic knowledge of or exposure to substantive/contemporary/analytic anarchist theory, so leftcom shit looked better.
My answer to this question is BOTH...
Having more folks isn't necessarily good.
An effective movement does require some filters, eg stopping abusers and opportunistic grifters at the door.
The upside of tankies is they draw away the shallow, status-driven authoritarian trash we never wanted.