I dunno. To be fair, groups of 6 (and more) outside have been going on throughout the entire pandemic. Standing in shopping queues, walking on our daily exercise, doing the dog walk, visiting the allotment. And yet, at least in the circles I move, compliance with the 2m rule has been conscientiously implemented...because we are still keeping a semblance of community awareness as well as self-interest. In itself, I don't think it should make much difference... but if going to shops, bars, schools are deemed acceptable, I think the uptick in infection will be very evident. The inside/outside thing is the point of danger, I think...because we tend to act differently when indoors whereas maintaining a reasonable distance outdoors is psychologically easier as well as physically more doable.
But, as usual, the message is deliberately (I think) left vague and ambiguous with the emphasis on numbers rather than circumstances...I have to think this wishy-washy approach is a deliberate distancing and preparation for scapegoating.