False analogy. Anyone who's graduated high school has some to a good idea what was taught them when they attended. Anyone with a degree from a university is on par with the education level of most teachers, and may be better educated.
So, it isn't like surgery where specialized knowledge is required. I think the vast majority of people can read, write, and do math at a level that they can understand whether or not their child is getting a proper education in those subjects. I'd say the average K - 12 teacher is more poorly versed in STEM subjects than many parents as well. Their liberal arts background doesn't prepare them adequately to deal with those subjects.
So, when parents object to something being taught, or the way it's being taught, teachers should damn well listen to those objections and either be able to explain why things are done the way they are, or what's going to be done to fix a problem pointed out to them. Telling parents to STFU tells me that teachers don't like being told they're doing a shitty job and why.
I'll add that this for K - 12 is utter bullshit (quoted from the above Tweet)
An educator's top goal is to teach students to think. Wrong! You can't think about shit until you are firmly grounded with enough knowledge and related skills to have something to think about. K - 12 should be about making students functional, productive members of society not philosophers. Remember, only about a third of those students will go on to graduate from a four year university. About half will get an associate's or post high school technical degree in some field. The rest are screwed by teachers prioritizing thinking over knowing.