The Jacobin published a good and not very surprising piece about how many union organizers are treated by their employers.
I, of course, work for a labor union and I will say that the union local I work for treats its organizers respectfully and takes its obligations to them seriously (though I should also add that I part of management, so perhaps I am not to be trusted?).
The thing is, this is actually something endemic to the progressive movement as a whole. There is a certain attitude too often taken that because one is working for the progressive movement, that one should not therefore need nor want better wages or sometimes, even decent ones.
Though my current organization doesn’t, but I have worked for orgs that do and there is nothing more frustrating than listening to someone who makes six figures explain why you it’s okay for you to make less than 40k.
Another effect os this is that is severely limits who is able to join the progressive movement. While those who hold progressive beliefs are very likely to be people of color and lower income, those can afford to work for the progressive movement are too often only those whose parents can afford to subsidize them, which is to say, predominantly middle and upper class white children.