Back to the op, ime every time I get shouted at/beeped at by drivers for being in primary or for riding 2 abreast is because the said drivers would like to pass without going in the other lane, and I would not like them to pass due to being reluctant of being squashed.
At times, the other lane has been empty, or we are very near at red traffic lights, or even on a 20mph road with speed bumps, but still, they must go in front.
Now, if even retired driving instructors that cycle think this way, what hope is there?
No wonder some new cyclists refuse to ride the roads!
I used to dread the aggravation: I'm older, slow, mostly ride heavily laden bikes.
Why should I always seek segregated paths, most of them inconvenient, with rubbish surfaces?
I really try not to hold anyone up, but if I don't have a choice and it happens, well, tough.
After all, when I have to slow to walking pace for a group of pedestrians on a shared path I don't go about ranting "they should walk single file".