Unsolicited wind blocking

Question for cycling community.

I commute with an ebike from work and home.
On my way, there was extreme headwinds.
Because I’m on an e-bike, I was going my normal speed of 20mph.

I noticed this man on those aero bikes, following me extremely close. I realized he is using me as a wind shield.

I did not consent to this. I don’t feel safe when someone is so close to me from the rear.
What if a squirrel comes out suddenly and I need to brake quickly? I don’t want to get rear ended.

Is this a normal behavior or did I run into an A?