if this becomes more widespread, this is one of the most chilling aspects. I don't think it takes much imagination at all for anyone to consider a future where something you said today that is totally acceptable by today's standards keeps you from participating in some aspect of society* in 10 to 20 years time. Think about how many public figures have been canceled for things they did that were socially acceptable 10 to 20 years ago. Now imagine tooling being developed that scans your entire social media existence for the past 10 to 20 years and then throws an automated exception saying that you can't register. Then imagine that you have no recourse because there is no due process and practically non-existent Google quality customer service.
* any sufficiently pervasive social network is a significant aspect of society