The types who have criticized my appearance in the past have been SJ the majority of the time from what I gather. I am male who has in the past let his hair grow out a bit. Why does this offend certain SJ's?
One thing to note is the age of the person criticizing you. In the 1960's, in the United States, long hair on men was socially a [purposeful] sign of disrespect for the government and/or reigning authority... rebellion against the norms.
By the 1980's, long hair on young adult males did not really mean this at all, any longer (IMO); but it was still associated with rock music, drugs, rebellion, etc., a lack of "discipline." (and it was still a direct assault on the "gender" barrier, with many male rock stars wearing female hair styles as well as makeup).
Nowadays with the cultural changes that have occurred, I think it is not a big deal at all, really. But still, any Baby Boomers and/or older generations are prone to see it as rebellious. Gen X'ers and younger are more prone to see it as a sign of individuality.
Side Note: I have also been harassed by an ESFJ for my choice of clothes and criticized by an ISFJ. Why do some SJ's think they have the best sense of style?
I would correct this to say they think they have an understanding of "appropriate" style. It's not necessarily the clothes and hair that are contentious, it is the manner and place in where you exhibit them and how.
Without details, there is no way to assess what is really going on. There are just generalities that might or might not apply to your situation.