I hate these assumptions too! I’m type 1 and a little fat. I don’t get the oh, if you just lose a little weight thing very often… I think because I am young and I work around a lot of medical people that know the difference between type 1 and type 2.
But I hate that assumption. Because, like you say, not all type 1s are skinny and not all type 2s are fat. And underlying that assumption, is another assumption that being fat is bad, undesirable, and automatically “gives” you diabetes, when it’s just one risk factor of several. And that type 1s are “better diabetics” or more deserving than type 2s, and that it’s type 2s “fault,” which is such a messed up and inaccurate assumption. And that anyone that’s fat needs to change their body and everything will be perfectly ok. Which isn’t necessarily true.
And… it also bothers me when type 1s get angry for being mistaken for type 2s and are jerks about it and but down type 2s. Instead of responding how you did, by discussing the stereotypes and being frustrated by stupid people thinking they have your cure when they have no clue what they’re talking about, some t1s respond by putting down t2s and trying to distance themselves from them, which sucks.