I like Jim's content but I wouldn't be caught dead wearing anything that associates me with the Sweetie Squad. Using themed merchandise inevitably links you to a fanbase and in this case one that has a deservedly bad reputation (and it's not hard to imagine why when you look at the last few pages of this thread).
When I see a Steven Universe clothing being worn by a grown man I subconsciously associate it with an excessive consumption of soy-based products, in the case of MLP-themed accessories my thoughts go to autism and sexual deviancy and don't even get me started on kekistan t-shirts.
A Sweetie Squad hat might not be as embarrassing as the above examples but we're getting there.