There are really the standards that classroom discussions of politics should center around. My opinion is that political screeds have no place in society, classroom or not. But learning to have a conversation with people you disagree with, learning to understand counter-arguments to a position you believe in, and learning to compromise should all be things that are essential to an educational experience.
I was in the debate club many years ago, and we intentionally explored potentially political topics that were in the news. I remember debating the US PATRIOT act and drawing the pro side. I disagreed with most the act’s provisions then and do now, but having to learn the arguments of the other side meant that I had to really think about why I opposed it.
It’s a lot harder to have emotional responses to politics and culture when you’re trying to calmly explain your position to someone's face. We should be providing plenty of safe, supportive environments, both at home and at school, for kids to develop skills like critical thinking and argument.
When we feel like some teacher is going to indoctrinate poor Timmy or Susie, we’re just admitting that we haven’t prepared the child to think critically for themselves.