Her last book had an anti-fascist message with Umbridge trying to take over the school. I didn't see anything having to do with socialism. Fudge believed what he wanted despite evidence to the contrary.
Fascist equals National Socialist equals socialist to me. The Ministry (government) was centralizing control of the previously autonomous Hogwarts by placing Umbridge there. That's socialist enough.
Anyway, Umbrdige reminded me of some of my NEA-affilated teachers & principals.
Note the Wesley twins reject government careers for the private sector :-)