Rush doesn't get deplatformed because the technocrat enemy doesn't understand radio. It's as simple as that. They live in the internet, which they are able to control, and they assume that everyone on earth lives in the internet as well–ergo, radio is a low-value soft target that they don't expend too much ammo on. Yeah, they listlessly snipe at it, but at the end of the day they just assume that the only people still using analog radio are Peruvian guinea pig farmers, and therefore harmless.
That's not to say that he hasn't fucked up from time to time–he absolutely has. But the fact he's still around doesn't necessarily make him suspect. It just means that the other side doesn't understand how the rest of of live, because they assume that everyone gets their political talk from an easily-bottlenecked podcast just like they do.