I think there are two reasons: choosing to change jobs on your own gives you ability to pick a time when it's minimally disruptive to yourself and your actual family, and then the pretend "family" vibe you cite is pushed by the employer in the first place. Companies insising on a game of make-believe where the relationship between employer and employee isn't transactional makes it hard not to be bothered by the hypocrisy. I agree that on average, the tech industry isn't as bad as other industries often are, but I don't see why that's a compelling argument not to care about the fact that it still could be better. There's nothing stopping me from wanting fewer tech layoffs and better conditions for workers in other industries as well (and in some circumstances even advocate for that even knowing that it might require changes to my own quality of life to achieve that; as a trivial example, I go out of my way to tip much larger than 20% when I use Uber because I'd rather risk getting ripped off than a driver not getting paid a fair wage for the work they do for me, even if it's at my own expense).
At the end of the day, everything is a balancing act, and the amount of change most of us can make as individuals is a drop in the bucket compared to the unfairness that people have to deal with every day. We all have to make judgement calls on where to take a stand and where to play it safe to avoid making things harder for ourselves without actually making a difference that ends up helping anyone, and if people are acting in good faith when trying to make those choices, I don't see any value in criticizing what they end up deciding. If anything, most of us in tech are probably in far more of a comfortable position to be able to speak out against employers (either or own or those in industries where workers are treated even worse), so I think there's a reasonable argument that it's more important for us to because of that. It's not a zero-sum game though; pointing out tech employer hypocrisy doesn't inherently take anything away from pointing out even worse things that other employers do.