He sounds like a control freak to me. I'd hazard a guess that he resents the idea that the others would have welcomed in a newcomer while he was away, and is reasserting the control he feels entitled to.

You could flatter him by asking advice, so he sees you as his protege. Or you could play it more confrontationally, because it's quite likely there are others in the session who find him a pain in the neck.

Or you could listen to some recordings with a view to finding some respected musicians with a non-ornamental style, and quote them as ground for playing the way you play.

I'd expect that if you go along with your instrument, and sit with it on the table, it won't be long before someone asks you to come on in.

Find another session if need be, but don't give up on playing. For every oaf like this one (assuming he wasn't just trying to be helpful, and didn't have the knack), there are dozens who welcome newcomers, and know that we all have to jump in somewhere before we can start swimming.