Many people grow up with dreams of being a teacher and making a difference. It is unfortunate that the path to that dream in NYC and many other cities obligates aspiring teachers to join the union. If they don't want to work for the cities and have diverse populations of students and decent educational equipment to use, they can work for parochial schools, at a fraction of the salary and a shadow of the benefits of public school teaching. Since the union is not a daily or even weekly touchpoint, most people would opt for the former and simply enjoy teaching their kids. I doubt if many aspiring teachers ponder whether they should accept a decent job with good benefits or not based on the political views of the union.
I rather seriously doubt that med school graduates would refuse a position in a prestigious hospital because of the political views of the union there, or person deciding to run for office would turn down the nomination because they'd have to deal with unscrupulous " Communist sympathizers, La Raza, Socialist Workers Party, et al." It's YOU, buddy, who should get real and stop talking out of your nether orifice.