Well a couple of people certainly went off me due to Facebook posts: Or it might have been 3 people actually.
Person 1 was a former colleague and friend. At the time I worked with her (early 1990s). At that timed she was very interested in yoga and spiritualism and also mountain biking. Her politics were fairly left, despite being American. She returned to the United States and took her much older partner who was from the European country we were both living in. Her DP only had a tourist visa and stayed on the US so therefore became an illegal immigrant. Over the next few years, my friend became 'radicalised' by her DP and became extreme right. She started posting about how brilliant Trump was, how dangerous vaccines wet and, ironically, how evil illegal immigrants are.
During the pandemic, when she posted about the dangers of vaccines (all bullshit), I often put in a comment with a link to what scientists and doctors say about vaccines. She got fed up this, messaged me saying I was very opinionated and then unfriended me.
Person 2 had similar views to Person 1, but didn't post such extreme things or as frequently. I sometimes used to question her views too (always in a polite qnd respectful manner). She unfriended me with no explanation.
Person 3 - I unfriended them because they kept telling me that my holiday snaps upset them because it reminded them that they hadn't been abroad - even though they had frequently told me over the last 2 or 3 years that they hardly ever look at Facebook. I got very fed up with this and said if they wanted to go abroad they should stop going on short luxurious and very expensive UK breaks and use the money for normal abroad trips instead. I was abroad again and kept wondering if my photos were upsetting them and in the end just decided to unfriend them too to stop the hassle. Having told me repeatedly that they hardly look at Facebook, they contacted me within hours to ask why I had unfriended them!