I really do not have any idea how people are making weird things look cool or acceptable. Some things are just not acceptable across the board. Just like a white person saying the N word is not going to be accepted around the world anywhere, some fashions are just not acceptable by people in the whole world. If a man wears a dress, and says he's a woman, it is not going to be acceptable in any logic based society.
I feel like I am going off track. Anyway, this was definitely weird to see. But as you said, this might actually be something which players do to Collab with some fashion brands and also increase the popularity of both the brand and themselves. But they definitely end up doing some stupid things like this.
In the case of Jimmy Butler, I don't see any relation to a brand or anyone promoting their product through Butler. What I saw is that he just tried to catch the attention of NBA fans, and he succeeded. Aside from being one of the best players (though underrated), Jimmy has a sense of humor, trying to make the league chill out a bit before the season starts. And look, we are talking about James Harden, and the event was well noticed.
This will pass; the real battle will start soon, and I believe that the Miami Heat is well-prepared, although they missed out on getting Lillard, whom they wanted. Lillard expressed his interest as well but ended up playing with the Heat's rival.
Jimmy just trying to be Jimmy, give the man the spotlight.