I also am not the biggest fan of the use of the term “ultra orthodox”. However the terms ultra orthodox and yeshivish are often used to describe the same people. In general the vast majority of such people where black and white etc. some don’t but the vast majority do. Now the same with Modern orthodox the vast majority don’t only wear that but some do. And there are shades of grey in between (or maybe shades of blue shirts) but anyways thats not the point.
From my experience its common for people who consider themselves to be modern orthodox/ YU/ left wing yeshivish/ whatever else you want to call it to show a lot of hostility towards the frum community. And although there are many in those more “modern” communities who are very makpid on halacha there are also plenty who are not, some perhaps only out of ignorance. It is not uncommon to hear the young people in such communities ask things like are you shomer? (referring to shomer nagia) Where as I haven’t heard that in other communities. So yes its possible im wrong but I’ve just heard enough similar stories from many people in person and these people like to bash on a regular basis. For example one person spits on someone and then all of a sudden its all the “ultra” orthodox who are horrible people.
I’m sorry if I offended you I did not mean to. Just as I was right about you not being “yeshivish” and you could probably guess with a good chance of being right more about me than I have writen, I think there is a good chance the person telling the story does not like “yeshivish/ultra/chareidi” very much. Again I am sorry if I have offended you.