The problem is that the Imperium already has a lot of the bad look at communism stuff already if you squint a little. They've also got a shitton of Russians.
I'd honestly be pretty mad if fictional races were 1:1 parallels of real world shit, even as part of some sort of social commentary.
The big reason I think that I hate Tau is that they're so fucking tiny and can't have any sort of impact on the setting. They should stretch across part of the galaxy, have settlements around the fringes, something. Instead they're a literal blip that only gets to join in on campaigns outside their safe suburban neighborhood if someone pays for their warp fare.