Be careful here. The "modern left" is not the ones in the US actually pushing laws to (by legalese and administrative decree) effectively censor opinion and material under the guise of being "too woke".
These days, any social media that allows "silos" eventually settles into such, and they are gate-kept. The strong silo-ing is also IMHO a byproduct of the modern social web of binary upvote / downvotes that fuel algorithmic feeds, a feature not present in the early days of the web, and (my theory) one that tends to reward the "strongest" opinions, which also tend to be the most extreme. "Left" or "right" isn't the problem I see regarding social media, instead it's the overall design. I don't know if Mastodon has avoided this (IMHO) cardinal sin or not.
These days, any social media that allows "silos" eventually settles into such, and they are gate-kept. The strong silo-ing is also IMHO a byproduct of the modern social web of binary upvote / downvotes that fuel algorithmic feeds, a feature not present in the early days of the web, and (my theory) one that tends to reward the "strongest" opinions, which also tend to be the most extreme. "Left" or "right" isn't the problem I see regarding social media, instead it's the overall design. I don't know if Mastodon has avoided this (IMHO) cardinal sin or not.