Filter bubbles have always existed in every society, and always will. People have always chosen communities and groups within them with behavioural norms, and those who defy the norms are ostracised or made to comply.
If anything, having means by which communities can separate partially without needing to fully isolate (e.g. if you don't like Twitter's moderation policies your choice is to cut yourself off from Twitter; if you don't like fediverse instance X's moderation policy, you can pick from several thousand other instances with varying degrees of concordance with or opposition to X's moderation policies, most of which can still federate with X) gives an opportunity to reduce those bubbles.
If anything, having means by which communities can separate partially without needing to fully isolate (e.g. if you don't like Twitter's moderation policies your choice is to cut yourself off from Twitter; if you don't like fediverse instance X's moderation policy, you can pick from several thousand other instances with varying degrees of concordance with or opposition to X's moderation policies, most of which can still federate with X) gives an opportunity to reduce those bubbles.