Son was suspended from school

I got a call yesterday from my sons principal. My son was involved in a fight at recess and needed to be picked up and she would contact me later about suspension details. I had my dad get him from the office and bring him to my house. My son tells me it was self defense. They were all playing basketball and his team won. The other kid kept calling them cheaters and bitches and would not let up, so my son tells him to "shut the heck up". The kid then pulls my sons hoodie over his head and throws him to the ground and starts punching him in the face, so naturally my son starts kicking him (other kid is significantly larger than mine) until his friends help him off the ground. Playground aids rush over and pull them apart while the kid is telling my son he's going to kill him.

So I call the principal and tell her I'm confused as to why my sons getting a two day suspension when he was physically defending himself from someone who's punching him in the face. She basically tells me since they were arguing and my son had smacked the ball out of the other kids hand that they are both to be held accountable. I say I don't expect him to lay there and take punches and she pretty much ignores me.

I gave up bc I was getting nowhere with this lady. I have parents of kids who witnessed the incident telling me I should fight the suspension bc their kids all say my son was fighting in self defense. I'm considering it but he gets to go back tomorrow and not sure it's worth fighting it.

Would you fight it?