This is a purely non-antagonistic contradiction, regardless of your opinions on the PCP. As for the RGS, they maintain a political line, which you have to follow if you want to get in, like any other party.

Maybe start by studying PCP, they have multiple volumes from the 1960s till now. But for that you have to study M&E, Lenin then Mao.

As for the answer, Maoist analysis is that there is always potential of an inner bourgeoisie forming within the party, because class struggle continues under socialism, and the bourgeoisie will do anything they can to gain power back. If that is universal, then so is Maoism. Continuous purges are necessary, and the proletariat needs to get rid of the existing remenants of capitalism not just in the economic base, but in the cultural superstructure as well. I don't think it is any different from what Stalin did, and I hold that this is the praxis of Gramsci's theory of cultural hegemony.

I don't really think anyone should look at self-identified Maoists on twitter and call them dogmatic, endless debates will not result in anything, the internet is not the class struggle. I think you should talk more with RGS, I don't hold them in any negative way, I've heard decent things from them. They are student groups afterall.