There's also a huge cost for taking action about this especially in the US. You can easily get thrown out of school, have your career destroyed or be deported.
This is mostly a US thing. Netanyahu and Putin are two war criminals according to International Court of Justice. Although Trump threatened the ICJ, this doesn't change that basic fact.
This. There are entire groups dedicated to rooting out any sign of deviation from per-authorized storyline and verbiage. It is particularly striking given that US considers itself 'free speech' bastion.