It's funny, because your standard for what counts as actual ageism is the conservative view on what is racism. They think the fact that black people are constantly under-represented and negative things are assumed about them, without evidence, is not racism. Only if it got to the extreme of saying something like "Well he must be a criminal because he's black" is racist.

You didn't know who Ed Markey was. Sure, that's ignorance. But knowing nothing about him other than he was very aggressively in favor of giving people more emergency aid and that he is a wrinkly old white guy, you concluded he must be at most a moderate Democrat/centrist. This is literally no different than seeing a black person at your job and calling the cops because "you thought you knew every employee" while also conveniently not calling the cops on any of the white people you had just not noticed you didn't recognize. That would still be racism, even if you never explicitly pointed out his skin color as the reason you doubted his place at the company and this is still ageism, even if you think you only noticed him because you thought you knew all the progressives.