no, I don't know him irl, but no, I'm also not assuming things about him
How are you not assuming?
What if he is a person concerned about social justice but realized that the vast majority of people are not. Because of this, he acts in a manner which would call people to action and stir them up for the cause?
I'm sure that at least one person in the world behaves in this manner.
But, don't worry I won't knock you for assuming. Assuming is how the human brain works, we build our knowledge of things based on experience. When we encounter a new thing we observe properties and compare it to other things and make associations. If the associations you make appear to hold true for nearly every case, you start assuming that it is true for all cases. This can steer you wrong sometimes, but then you just adapt your definitions and wait for a little more evidence next time. Clearly Caribou had not encountered many gay people who behaved as Frankie had before. Clearly you have not encountered (that you know about) anyone concerned about social justice who practices the hypothetical situation given above before.
Basically, we all assume things and that is how our brain works. Sure, you should stop people from assuming things that are incorrect or potentially offensive, but don't get worked up about how the biology of the brain works.