No there's not, you just haven't bothered to read up on the issue.
Rioters wanted a toxic senior leader fired for well-documented lapses in judgement. Instead he was given 3 months off and re-hired when the dust settled. The employees personally impacted by this are unable to pursue legal recourse thanks to forced arbitration.
But even assuming your explanation is correct, it is incomplete. Why now? This guy has been with the company for a while. He is hardly the only bad actor at the company, so why does his case merit more focus? Have a confluence of factors reached a tipping point? Do employees feel secure enough about their status that they can make this move?
The employees are fighting this particular case of injustice because they care about doing so, and because you don't solve a big problem by doing nothing; you have to start somewhere! This is the start.
> But even assuming your explanation is correct, it is incomplete. Why now?
The offender was brought back on with no long term consequences for his behavior, and now 100+ people have found the courage to coordinate and walkout to express their disdain towards senior management that thought this was ok (to put a toxic individual back in with people that are uncomfortable around him). Do you think this shit gets organized in a few hours around the water cooler or at a single happy hour?
The group walking out clearly articulated their reasons, that's on you if you can't bother to read up on it.
> Do employees feel secure enough
There's the National Labor Relations Act, plus California protects against retaliation when speaking out against working conditions.
Because we are in a day and age where these efforts actually have a chance of success.
10 years ago, the vast majority of people would hold the same toxic attitudes that you hold, and the concerns would be dismissed.
But not anymore. Things are changing. And it is now possible to hold horrible people responsible for their illegal and immoral actions.