Having needed to hire for engineering teams, I think the iced coffee would be a big deal if the position was client facing and wouldn't be if it was internal.
The answer for me of "who defines professionalism" is the client. If the effective end client is me, I don't care. I'm pretty lax and chill.
However, if I'm hiring for a client facing role and you bring an iced coffee, you are saying that you don't know or don't care about client expectations and that is a red flag. I work in an industry where it is still the expectation to wear a suit and tie to certain client meetings. If you can't play the game with me, how can I trust you to play the game with the client?