His possible assumption: that I am stupid because I have a rollator.
Though I guess it's possible he was feeling awkward about the rollator and was just saying anything to fill the space around his awkwardness. He didn't have to say anything at all.
2. I was trying to get on a bus. I asked the driver if I should get on by the back doors, because the aisles are too narrow in some buses. He asked if the rollator could fold (to leave space for a wheelchair user). I said "yes, but it's difficult for me". He said "yeah but you're young," and flashed a smile as if to tell me that I am 'not that disabled' because I'm young. I said "just because I'm young, it doesn't mean I'm not disabled," and I went through quickly to sit down.
His possible assumption: that I'm not disabled because I'm young; that he can tell what I can functionally do just by looking at me; that I would benefit from encouragement to do things I find too difficult as a disabled person.
I shall update with further stories as they happen.