The "iced coffee to an interview" thing is such a good case study in Gen Z not being able to pick their battles
Everything has to be some dramatic example of oppression or ableism or "corporate overlords" instead of...just the way things are
You don't wear white to someone else's wedding, you leave a tip when it's customary to do so, these are just social conventions that make you not look rude
An iced coffee doesn't matter that much to you as the interviewee. You will survive going 1 hour without an Iced Brown Sugar Oat Milk Shaken Espresso
But it COULD matter to the person interviewing you. Why risk it? Why die on that hill?
You may think it's a poor proxy for professionalism, you may think a good employer wouldn't care
But if someone tells you "Hey, this is not universally acceptable, it could risk your success," and you insist on doing it to make a point, that's your own dang fault