Not all analogies can be saved, nevertheless let's try:
the town = the TCP/IP suite of protocols (UDP, QUIC, etc. included)
the public town square = DNS
a booth selling vegetables in the public town square = a domain, "foo.com", publishing whatever their opinion is about reality and everything else
A great lie told again and again by "social media" domains is that they are "platforms", but a platform is meant to sustain something else beyond itself. "foo.com", "twitter.com" are merely individual booths, where all the value is owned by the person/company owning that domain, irregardless of how "easy" it is to "post" on "foo.com" and how difficult it is to setup a new booth/domain on DNS: DNS is that platform we have been hearing ad nauseam.
And even more, a domain, such as "foo.com", or "twitter.com", or "tiktok.com", is fundamentally someone's estate, owned by a master [1]: it's a glaringly obvious contradiction in terms to say that a domain could ever be a "public town square".
Entering and adding value to someone else's domain is akin to belonging to a feudal master, a technofeudalism if you will [2]. And some tehnofeuds are great, I personally enjoy "github.com", but believing that "github.com" is a "public town square" for code, not backing up your work in other places, it's at the very least irresponsible.
[1] https://www.etymonline.com/word/domain#etymonline_v_13918
[2] https://www.youtube.com/watch?v=SMSNpq4K67o