The post illustrates the 3 things that make communism/marxism fail.

I am trying to work in a political group but I have no motivation to work on it at all .

Like any group, most of the members don't do anything.

"Kind of the whole point" is violently overthrowing capitalism

Capitalism isn't going to topple itself, so this makes sense from the lens of socialism, but they need to set up the structure that will replace capitalism, and they don't, which means that if they overthrow capitalism, it will be replaced by something eerily similar. They could simply implement socialism on a small scale, work out the kinks, and gradually expand in scope as people see their success and willingly join. Those success stories are few and far between because those smart enough to try this are eaten alive by their very supporters.

It is a science of totality (or what Althusser calls the complex whole) to achieve proletarian liberation

Socialism is its own language as it redefines words in ways different from how everyone else uses them which is a great way to isolate people.