What are these so called relationship skills that single people don´t have?

As a late bloomer i have been told that dating will be especially hard for me because i have no relationship skills. When i ask specifically what these skills are they usually name: empathy, communication, boundaries, compromise etc. But these are skills that you should have already up from simply interacting with people. Better yet, your parents would have taught you this at some point. How did this become something that most people apparently do not have? Or am i missing something?