That is fine. You could have said your welcome or sure thing. But what said is fine.

at least they thanked you for holding the door

Are you Canadian ? :)

Not the worst reply. “No welcome,” “your problem” or “not a pleasure” would have all been worse.

Do you say "you too" when the waiter says enjoy your meal?

That's terrible! I'm so sorry that happened to you. There's really no way around it, you're going to have to leave the country and start over to escape this great shame.

Well - you hold the door - have a nice long look at their lower back side as they pass - when they say "thank you" - you reply "thank yoouu" Not creepy at all 😂

In the grand scheme of things barely a blip in life never mind an FML.

You think that's bad. I held the door open for a girl the other day(as i'd do for anyone), all I got was a slap in the face and called a "misogynistic pig". All anyone in the shop heard was the slap and her screaming at me, I got a lot of dirty looks. Not the first time something like that has happened.