Yeah, I think she's assuming that, since some of those people are IRL friends, that means they're not terminally online people.

I'm around finance folks and they're all trapped into the same crypto-and-AI influencer bubble, but they would never be able to tell because their physical connections are also finance people who are likely to be caught in the same corner of the algorithm. So their real life conversations reinforce the worldview that the internet presents.

This is likely the same case. The author might not be involved in certain online spaces, but she shares characteristics with her friends who make them all be targeted by the same bubble, so everyone she knows echoes that space to her.

With this post on HN, her 'puritan echo chamber/bubble' meets this 'nerdy/intellectual echo chamber/bubble'.