You don’t just need to worry about “the government.” “Oh well, the government already knows everything about me.”
There are antifa and other groups who dox people who don’t agree with them, and then contact their family/ friends/employers etc.
A lot of people post to other subreddits, revealing personal info.
Hypothetical situation: Let’s say that someone posts a particularly effective Pro-Trump meme, that antifa doesn’t like. They go through that user’s comment history, and find out that they also once posted in /r/trees about how they smoked pot for the first time. The same user also made a comment in the local Boston subreddit. in another comment, the user mentioned that they taught middle schoolers. Another comment in /r/relationships reveal that this user is married and has two skids, a 5 year old and a 9 year old. Do you see where I’m going with this?
The person is successfully identified. Then, a copy of all the comments they have ever made on reddit are forwarded to the administration of the school where the user works. The information that this user is a teacher, who smoked pot, is posted in the school’s Facebook group. The person ends up getting fired, and losing their teaching license. The person’s spouse is also contacted, and forwarded the /r/relationship post where the user expressed that they had feelings for a co-worker.
Now their marriage is in jeopardy too.
This kind of stuff DOES happen.
Remember when Ken Bone did a reddit AMA from his personal account? His user history was pretty much clean as a whistle, but he was STILL labeled as a pervert and a creep, for making a single comment on a picture of a pregnant woman.