They get paid a salary to do a job, not to protest business decisions. If they want to protest something, they can, but they shouldn't expect any protection from being fired because they're literally refusing to do the job they were paid to do. Do you think a book store employees should receive protection for moving all the books on evolution to the fiction section?
Long have engineers and other workers complained of clueless MBAs. Why go to bat for the pointy-haired bosses? Haven't you ever worked at an org where product leadership screwed up, leading to layoffs anyway? Or management overruled the technical concerns of the engineers? Or pushed them towards something that was simply unsound for the product and the business as a whole? Pursued strategy by fiat, where the only check against their power is the board?
People imagine tech unions will just be a rehash of Industrial Era blue collar unions, but they have the potential to be something more- a way for the rank and file to finally have the clout to push back against bad engineering decisions from poor leadership.
There is at least one example that comes to mind where a union forces corporate leadership to make business decisions that could potentially help the company stay competitive- and thus protect all of their jobs:
https://news.ycombinator.com/item?id=13986889
Finally, as shareholders themselves, why shouldn't employees protest against questionable business decisions? What stake do they have in a company if they are expected to unthinkingly carry out orders?