I see this point made a lot, and people seem to think they are disagreeing when they say it but the fact that some people have abusive parents is the exact same point the poster made.

Kid has rich parents -> has privilege compared with those that have poor parents

Kid has non-abusive parents -> has privilege compared with kids with abusive parents

Has parent with some skill or trait to model -> privileged compared with kids that don't who in turn are privileged compared with kids who model bad behaviour from their parents.

Kid has parents -> privileged compared to those without parents.

There lots of things that make you who you are that you don't immediately consider to be contributing to your relative success in life, that's what the concept of privilege tried to remind people of.