Irena, I would absolutely report this problem: to the SPED supervisor in the school, the one in the district, and to the principal.

If none of them offers a plan for addressing the problem, I'd go to the superintendent but also start seriously shopping for other school options. It's hard to change a whole culture. If there's one person making comments, you can remove DS from their care, but if it's the whole staff, that's really tough to fix.

Hang in there.