This is exactly right. You can hold a view that is perfectly acceptable within mainstream society right now, and find that 10 years from now that view is considered extreme or dangerous. If you have a public and searching history of espousing that view, you could suffer very really consequences as a result, even if you know longer hold that particular view.
I think you would have a pretty hard time finding examples of this in somewhere like the US:
* Few things go from 'mainstream' to 'extreme' anywhere near that quickly.
* If something does make that transition, there would be hundreds of millions of people who previously held the view and millions of people who previously endorsed it publicly.
* People care about your current views, especially on topics where lots of people have changed their minds. In cases where I wrote about something and then later retracted it, I've never had anyone treat that as if I still hold my previous view.
On the contrary, you can have a live example in the US today, and you could have found another one six years ago.
What's interesting is he generally is aware of groups of people that should not do so, like those who are abused, but does not consider the possibility that everyone can become a target (through regime change for instance).
I suppose the most frustrating part is his example of employers turning down people for sharing too much on social media, which should be normalized, but someone not sharing on social media should be penalized for hiding. It's a tad concerning, especially as we're coming to terms with the real damaging effects of social media mentally.
[1]: https://www.jefftk.com/p/privacy-tradeoffs