I also don't buy most of this crap. I've heard the "doctors and nurses" line quite a bit, and, yeah, no. Health care workers literally signed up to treat sick people; it's not just part of the job, it's the foundation, the reason their job exists. Teachers signed up to work in places with policies that are directly designed to protect them from illness (says every parent who has ever rolled their eyes at the "24 hrs after the temperature hits 98.6" policies). Now, I think health care workers deserve medals and raises and our everlasting praise and respect for what they are doing. But that doesn't mean that people who didn't sign up for that deserve to be criticized and disrespected.
I also think there is a lot of longstanding resentment about the "cushy" deals teachers have -- the alleged 6-hr workdays and summers off and pensions and job security and whatnot. Now, I was raised by teachers, so I know what that actually means -- the low pay, the many many extra hours out of the classroom, etc. But most people don't actually see that. And in fairly typical human fashion, people who have it worse in some manner voice their anger at the teachers unions for negotiating reasonable terms, instead of trying to change the de-unionized system they are stuck in that gives them no bargaining power to improve their own lot.
But another part of the reason that this is coming up right now is that a lot of people have had to deal with teachers who basically phoned it in in the spring -- who treated the shutdowns like a paid vacation. Now, I don't think that's even a large number of teachers; the teachers I know actually spent a lot more time than usual trying to transition teaching to an online platform effectively and basically worked their asses off trying to keep their students involved and engaged. But it's always the bad examples that stick with people, right? Like the HS junior who needed to take 3 APs, and whose teacher in one of the subjects basically didn't bother to do jack once school went online. Or the kid who had finally worked her way up to honors track in writing thanks to a lot of hands-on help from her teacher (kid was not a native speaker and started in remedial clsses in ES), and who floundered when everything went online. Or the kid stuck in a rural school with half-assed teachers in the best of times, some of whom literally did not hold even a single class after everything went online.
In all these cases, the parents got to watch their kids getting hurt, up close and personal, day after day all spring. And yet they are completely powerless; the school board seems to be focused on protecting the teachers, and while it makes noises about the good of the kids, there's no action taken against the teachers who totally checked out, and nothing but fluff and empty promises about how the schools are going to take care of the kids who don't do well in the online environment for whatever reason. And the whole profession gets tarred by the (in)action of a few bad actors (ask me how I know - I'm a lawyer!).
Add that to the frustration of parents who still have to go to work regardless of the risks, and who now have to find childcare for their own kids (thus increasing the risk that the kids bring the illness home to them, while the teachers stay protected), and, yeah, you get resentment. Think about it from their perspective: your taxes pay teacher salaries. Teachers are advocating to keep kids at home. That means that you as parent now need to choose between paying extra money for someone to watch your kids during the day, or quitting your job and forgoing your income, all while still paying exactly the same in taxes. So the end result is that the teachers still collect their full pay, while the parents take a huge financial hit -- and end up having to do half of the teacher's job to boot.
Again, in most cases, it's not the teachers' faults! A pandemic hurts everyone; no one has it easier or better than before. And better government management and supports could relieve some of those burdens, but we don't have that here. But all of that is invisible anyway. The part that is visible is that teachers appear to be looking out for their own self-interest, even though protecting the teachers means that we parents bear an increased -- and in some cases unsustainable -- burden.
Of course people are mad. Our system make it a zero-sum game, where protecting teachers means fucking over parents.