Propertarians use "capitalism" and "private property" in revisionist, ahistorical senses to mean idealized concepts that don't match up to their statist forms. Left libertarians let these words keep meaning their statist form and use "anticapitalism" and "personal property" to mean the same things.
The only disconnect is certain features of statist "private" property that actually aren't sustainable without a security monopoly that go uncritically examined by propertarians and are often focal points of left libertarian critiques, for example landlordism. These tiny little areas get blown all out of proportion into a giant ridiculous error in reasoning that we are somehow on fundamentally opposing pages.
There are people who benefit from preying on this fear, some of them are propertarians trying to shore up movement hegemony to keep their own think tanks and personalities in a position of dominance but most of them are statist politicians and cronies who know full well why they're protecting the ideas from which they directly benefit.
It's up to libertarians to be smarter than that, and prioritize #bottomunity over semantic barriers to communication.