I believe that any pure "ism" is a bad thing. All of the various "ism"s I've learned about have both good and bad aspects to them.

The ideal system is a mongrel, mixing ideas from the various pure ideologies. In fact, this has largely been how the US has done things since the US started, and has been one of its greatest strengths. Looking at US history, there have been several times (including now) when the nation has veered towards an ideological purity of one sort or another. That has never gone well.