Question on ":3"

I'm okay with people expressing themselves with ":3" and other like I guess cute(?) emoticons and images but for some reason I get decently annoyed by them, like one example would be for me that some of my friends who are in a depressive state currently when I pressure them to eat food or something say stuff like "No :3" and "You can't make me UWU" and it ticks me off in a way, I used to be depressed and developed a eating disorder from that so maybe that has something to do with it. Another situation I see this being used is in a dismissive or bratty way in an argument instead of actually talking things out and trying to solve stuff y'know. idk, again I'm okay with people expressing themselves in that way but I'm wondering why exactly it ticks me off.