I think they are referring less to the actual virus and more to the rapid deterioration of our discourse and politics that accompanied it. Or at least this is what I might mean when using "COVID" as an epoch.
That has been happening way before Covid.
IMHO it started with the internet. Pre-internet the flow of information is gatekept by traditional media - newspapers, radio, TV, … etc. Everyone watched, listened to, read more or less the same things. This resulted in a more uniform set of opinions and more common ground between people.
The internet broke all that. People could choose what they watch/listen/read and different people picked different things, coming to very different conclusions. In the past you could ask someone if they watched X last night and there is a decent probability they did. Today it’s much harder to find common ground - you could both be on YouTube but watching completely different things.
Edit: Don’t just downvote. You got a problem with this post, say something.
The internet though is mostly chaos. There are gatekeepers, e.g. Google, but they don’t curate much - using a blacklist approach rather than whitelist - and instead just organize the information making it findable.
Niche ideas get air time and now compete in the market place of ideas.