I get what you're saying. I only have about a year of experience with organizing myself, but I think the kernel of truth to the idealized "offline left" is just the fact that having real world shit in front of you puts into perspective how meaningless all of the online shit is. My local DSA's got tankies, anarchists and socdems (mostly socdems), but nobody really cares what your tendency is because what's important is that we [insert local issue here].