I could be wrong, but it appeared to be a compression knee high. At first, when I saw it, I made my assumptions of it being worn for medical reasons and did not think much of it.
After I reflected on it, I realized that it never came across as uncool or gay or effeminate. I think that I came to the conclusion, because of the person and the context.
First of all, the boy was playing street hockey, therefore, any legwear that is not frilly or feminine in colour would come across as sportswear.
Second of all, the colour of the knee high was a pasty opaque
skin colour, so you can kind of guess that it was not what gay boys and men typically wear.
Third of all, he only wore hosiery on 1 leg. Many athletes wear some kind of support or knee brace on 1 leg. Gay and effeminate men do not typically wear hosiery on 1 leg to look attractive.
Fourth of all, this kid did not look particularly fashionable. He did not look unfashionable, either. The whole point is that he looked average, which is very untypical of the gay and effeminate stereo type.
I am just amazed that we could learn something from an average looking kid.
Thank you for reading!