First class example is that evolutionary criticism (missing intermediate species or disputed claims of finding them, Darwin's doubled-down denial of genetics, etc) is completely forbidden in US schools.
They're not "completely forbidden", and they're certainly not forbidden in private schools. What is forbidden is using petty nitpicking of details, which are at best only marginally relevant to the validity of evolutionary theory, to advance religious doctrine, which is the only reason these issues are ever raised in the first place. If you want religion taught in public schools, move to Iran or some other country where superstition is mandated by law.
The idea that questions about evolution are only raised to advanced religious doctrine is a bit of a religious doctrine in and of itself. Literally the moment that anybody questions anything main stream the immediate response is that those people must be backwoods religious extremists. You see it EVERYWHERE. Somebody raises questions about monetary policy and excessive spending and people immediately go straight to conservative therefore religious. Anybody had the gall to suggest that it was possible for some people to be predisposed to have a negative reaction to something in a vaccine you'd immediately hear "right-wing-religious-nut-job" thrown into the conversation somewhere.
At some point public branding began happening that if you ever dare to discuss an issue, point out flaws, or raise dare I say "valid" discussion points that your question was invalid simply by invoking "right-wing-religious-nut-job" in the conversation.
The sheer fact that so many people immediately use that as a go-to rather that even thinking of defending any questions would seem to indicate that those people feel their own doctrine is being questioned, which makes the idea of those people calling others extremist nut jobs kind've ironic.
One of my all time favorite quotes:
"The test of first rate intelligence is to hold two opposing ideas in the mind at the same time and still retain the ability to function." - Dwight Whitney Morrow
There's a lot of people who believe themselves to be intelligent who cannot allow themselves to try to see things from another angle. Nobody holds a viewpoint strongly without having a good reason for doing so. If more people recognized that and tried to understand the other side you'd see a lot less vocal hostility.
Odds are very good that if you feel strongly about something there are a whole lot of times where you're right and a whole lot of times where you're also wrong.