The 'isms are better thought as points of reference for your political views; for example someone saying “I’m an $personist” is basically saying “I agree with what $person said/did in most theoretical and practical matters”. They are useful, specially as they help you to understand what the other person defends, e.g.

• a Maoist is likely to put heavy emphasis on rural workers
• a Trotskyist is likely to believe the revolution should give no fucks about borders
• a Dengist is likely to downplay the differences between market vs. state-planned economies, seeing them as just tools for an end
• a Luxemburgist is likely to raise criticism against any “higher” role of a vanguard; etc.

So they aren’t problematic on themselves. You need to watch out for dogmatism, though; just because you’re a $personist doesn’t mean you should automatically clap to every single thing $person did or said.