I think he was just saying that a lot of times "privilege" as jargon is a little different than the word's common usage. So, if you were making a point where the welfare theorem of economics made sense to bring up, you might post a link and say something like "it's important to understand this if you want to continue the conversation."

In my opinion, what he did was completely appropriate, not condescending, and helpful and I wish you wouldn't have just blindly classified the action as a liberal tendency.