I live in a more conservative area (in a blue state) and even though our teachers’ unions are powerful political entities, at least no one in our school district would dare send their propaganda to the parents.
One thing is clear - your school district’s ideologue teachers are pit-bulls off the leash. Telling them to go to hell may have consequences for you or your child (leftists are vicious like that) while doing nothing also seems unbearable.
Define the sending address as spam.