While the risk is obvious, what is the alternative ?

You can go down as a number on the spreadsheet, or you can show everyone else they are also numbers on a spreadsheet.

Her behaviour is a first step towards a different workplace. The effectiveness is questionable, but what more can a single, non organized individual can do ?

They could have quoted someone else who made the same point. Instead they chose to give more attention to a troll.

It’s not a cogent point but a distraction: as an authoritarian, Owens is naturally predisposed to assuming the company is in the right but a more accurate framing recognizes that this was not HR doing their jobs but HR lying about someone to make it sound like they were being fired for cause. Doing their jobs would have been “we’re doing a layoff, here are the terms of your severance”, and recognizing that Owens is an unreliable source is important for not letting her framing shape the discussion.

No. Anyone can form a superficially cogent argument when they don't need to defend it. This one is fallacious because it assumes its conclusion (hard working managers doing their jobs, rather than the reality of being unable to articulate what expectations the laid-off employee failed to meet).

Further, engaging with bad actors (who are generally cynics rather than idiots) normalizes their standing as commentators/public figures, and gives them opportunity to push shitty ideas into public discourse. They're PR professionals who understand how to exploit the dynamics of social media very well and imho to the general detriment.

Credibility matters. If someone is equivocating genocide with “making Germany great again”, it deserves to be pointed out and their testimony taken with a huge grain of salt.

I was under the impression that the German economy was vastly improved under Hitler, so I think that point at least is valid.