Well, being a cross dresser I obviously vote no, he shouldn't be banned. Clearly, this situation really doesn't have anything to do with expression of gender and I "get" that too but . . .
I think I could support something along the lines of "Hair must be clean and combed/brushed". This addresses hygiene and good health, something that schools and governments have good cause to concern themselves with. To tell people how they must cut their hair though is taking far too much liberty with someone's rights. It is the decision of a child and their parents how their hair should be styled and it's none of the schools business.
When you read the article, there are comments from readers at the end. One is from a teacher ranting that parents should follow the RULES (She capitalized this over and over), implying that this teaches the children to follow the RULES, etc, etc.
It is sad that anyone responsible for teaching children lives with their mind in such a small box.
There were once rules in the US that black children and white children should not play together.
There were rules that you must be the same race to wed.
In Nazi Germany there were "Rules" that allowed them to incarcerate and slaughter anyone that did not meet their ideals.
Clearly some rules should be questioned.
Clearly some rules should be changed.
Clearly some rules should be removed.