Based on the QA people I've worked with over the years it can be grueling work with an unusually high level of responsibility and, from what I've seen, low pay compared to developer salaries. Seems like an obvious part of tech to be at the forefront of unionization.
As for the companies fighting tooth and nail against unionization attempts, I don't blame them any more than I blame a dog for eating food I drop on the floor. It's just what they do. If we want a more equitable playing field for unionization we need to support policies and politicians to make that happen. Waving fists at for-profit enterprises accomplishes nothing.