Same story in Bristol city centre on the harbourside too - so I can certainly understand why a catch all rule about it has been put in place.
Whilst I understand the points about businesses and customers who have behaved sensibly, it is much simplier to have a blanket policy than required local licensing officials and police deal with such issues. Though I am still sad - especially as it means I won't be able to get local beer or lovely cocktails from the bar around the corner from me!
The same logic applies to why pubs had to close in the first place.
It is probably the case that the pictures on TV of large groups of people all mingling in city centres, hugging, and wandering around drunk side by side, would be responsible for a good bit of virus spreading. The scenes of these large groups and the scenes inside and outside busy venues would make some think that all pubs were super spreaders.
So the pubs and restaurants were closed.
But of course this is a catch all policy which means that the small local pubs in the villages which never get anywhere near as busy and don't have marauding gangs of drunks queuing outside the doors or propping each other in the streets also get closed, as do small local restaurants which may only have a handful of tables. In reality these smaller local venues out away from city and town centres would never be a problem - many visitors are locals and regulars and perhaps of a more responsible disposition, or just walkers having a quick pint by the fire on the way home after coming down off the moors.
Very difficult, nigh on impossible, to make rules which allow some venues to open and some to close.