I'm going to regret this but.........
Public space is for many things, but the roads are (amongst other things) part of our national transport infrastructure.
There are lots of lovely places to travel side-by-side and enjoy good company or a nice chat.
I think the road network is not necessarily one of those places.
(Off topic here but what other things are roads besides part of our national transport infrastructure? Or am i being thick here?)
Anyhow.... not sure of these lovely other places where one can cycle side by side. There are precious few cycle paths around the place, and those that are decent width are generally shared with pedestrians and any speed over about 8mph seems to be frowned on by those with kids / dogs / pushchairs also using the path. Plus you can't really go side by side on these paths
because of the other path users.
Which i guess is the 'don't ride sidy by side on the road' argument - we can't (or shouldn't) cos of the other road users?
What's the problem with riding side by side on a wide road, or a quiet country road, or just on a normal size road? Any time i've been side by side with someone, we drop into single file when we hear a car coming up behind, let is go past, and then assume side by side-ness again. Are we really suggesting that decent cyclists kicking along at 18mph and more, and having a chat as they go (wish i could do that!) should not be on the roads side by side if it's possible to do that?