Gobsmacked at these responses, I’d be furious! There’s no way of knowing for sure what somebody’s size is from looking at them, that’s nonsense! I know a tall and very thin woman who is a size 14 because she has an unusually large pelvis which isn’t visible from looking at her.
OP, I’d be putting in a complaint. People can roll their eyes all they like but this is that sort of low-level bullying that goes under the radar as it’s small enough on it’s own to look petty to others if you say anything, but actually it’s cumulative and is, in reality, insidious when it’s an ongoing pattern. I’ve been there.
I had a manager who did this shit. Lots & lots of little things, daily, which were never big enough alone for me to look anything other than a daft cow for complaining about it. Had me dreading work in end. I never got him disciplined but wish I had from the start, regardless of how ‘ridiculous’ some thought I was being.
You haven’t said whether this is part of a pattern of behaviour from them but if it is, please nip it in the bud.