I do think the disrespect is a problem, if only because it makes your audience less likely to listen to you, and that should matter.

But anyway.

Support your kid. Argue about the suspension to the district. Ground him for the length of the suspension, sure, but also help him figure out how to better argue his position. (Unfortunately, given your initial support of the administration, you're unlikely to have his full enthusiasm, there, but you can *try* and regain it...)