Comment by ZainRiz

Farnam Street has a great blog post supporting what you just said:

That most people only express things to people that they thing would be accepting of what they said. Even if they might not agree with it, they'll at least accept that it's okay to hold those opinions.

Once you cross the line into "Expressing this opinion will cause negative social consequences to me" then people start self-censoring.

https://fs.blog/2020/09/spiral-of-silence/