Comparing a physical space to a digital one is absurd.

Regulation will be used suppress speech and to further serve their paying customers: advertisers, politicians, special interest groups, corporations.

These platforms are already on their way to becoming sterile and for huge money incumbents, much like how cable tv is today.

If they have to be held accountable for the things their users do, they will simply wall it off even more, ban anything that seems slightly outside of the Overton window/status quo, and there will be absolutely no recourse for small content creators who are unfairly or wrongly banned.