It's a mixture of propaganda, infighting, infiltration, lack of organisation, and action.
In regards to propaganda, the media is often quick to subject us and commodify a spectacle of communism breeding poverty, producing death tolls in the millions, and being a super-power state as opposed to establishing a stateless, classless, moneyless society. It's similar as to how people view anarchism to be "ay lmao smash everything, listen to punk rock and chuck molotovs while drawing edgy A's"
Even though there are various refutations to the black book of communism, by historians and the like, it hasn't stopped it from being the go-to book for right wingers. It's a very effective propaganda tool conservatives and liberals are quick to start preaching on their soap boxes, while they shill for a system which relies on the exploitation to keep itself afloat. Even if you were to disprove lies told about the USSR, and how they exaggerate its death toll, approaches to ML communist parties are still going to be taken with a grain of salt, especially when they hold figures who are demonised by the west in high regard. Other contemporary examples is the propaganda pieces told about the DPRK, especially when you have known escapees who are paid to lie about the DPRK and spread propaganda.
I think you covering the infighting based on revisionism is also another thing. While I'd offer immediate support for a Hoxhaist militia to bunker down against revisionist Dengists, there is still the propaganda aspect you have to look into. And that's not dispelling the fact that you might have cointelpro deliberately screwing with your actions.
In regards to overcoming the problems, shifting the overton window to the left is certainly a goal. Creating propaganda of your own can certainly help dispel notions of Stalin being a "communist" or Marxist Leninism being a dead ideology. If you really want to go fully into it, Cockshott's economic system would be a step in the right direction as it deals with the material conditions as they are now.
Go out and hang out with other leftists, see how they operate, what they believe, argue and socialise where you can. More often than not, they'll fill you in with what's going on NOW and what YOU can do to act on it. Go to meetings that cover strategies on how to protest and riot. Verse yourself in how to organise grass roots movements. I recently got invited to a FLAAC meeting and they'll be teaching me some tactics to use in direction action when dealing with mining companies.
If you can train yourself how to fight, do so. It could help in the long run. Also, look into other forms of praxis. It's highly unlikely that the revolution will go your way. Learn to be adaptable. There's a huge anarchist movement in Europe, learn from them, and what they do and adopt their praxis into your own where you can.