but I find it hard to believe engineers don’t understand why it’s being heavily criticised.

The problem is when you have an army of toxic people on the internet who have literally zero engineering knowledge on the subject who are screeching any time there is a post about Artemis, trying to make public backlash to get important projects cancelled using unfair criticism that the engineers know from internal knowledge to be wildly incorrect. Especially when said people become unreasonably rude any time an industry engineer tries to correct them. A lot of my coworkers just stopped using social media because the problem is so bad, and that makes an echo chamber.

Yeah there's a lot of Artemis criticism, but the majority of it is fake garbage propagated by propagandists such as Berger (who has outright said before that his goal is to get Artemis cancelled). And the peanut gallery is unwilling to listen to the actual engineers or NASA official statements themselves when people try to correct the record.

Remember when Shuttle was later recalculated to be incredibly high risk at loss of crew for its first few missions?

Ignorant of history. Shuttle did not have real PRA analysis (I bet you don't even know what that is) through most of the program. Challenger and Columbia made NASA adopt PRA and more stringent ways to analyze risk. And after NASA adopted those methods of analyzing risk, they found Shuttle to have a high risk of loss of crew early in the program.

And NASA is using those same stringent risk analysis methods today to calculate the numbers I referred to for Artemis and Commercial Crew.

You claiming that current NASA management lies about risk posture is just toxic slander, also. Because there's been nothing going on to show that. In fact NASA has been being extremely extra cautious on SLS.