What a moronic reaction! While I don't really care if my roommate sleeps on our couch, one of the basic requirements of any home is the ability to use the bathroom at any point when it's not occupied. If this is going to feel like the place I live I have to know that I can take a crap at 3 AM, let alone having to piss at 9:30!
This is entirely an internal issue. I know what my roommate's potential reactions to being awoken by me are. He'd either roll over and go back to sleep, go to his bedroom and collapse on his bed, or get a cup of coffee and try to do some late night work on his PC.
I'm not an unassertive person in many situations. I am not a shrinking violet. Yet for some reason I have these weird impulses of anti-entitlement that serve no constructive purpose. It's one of my major dysfunctions.