It was deliberate to scare you there are a fair few maybe the majority of those on racing bikes do it. They expect car drivers to give them room but they don't think they have to give cyclist or walkers any space. If you are passing another cyclist you give them just as much room as you would expect from car driver and you let them know well in advance with a shout of "coming past"
Liked your post though I'd lean towards the "fair few" rather than accusing the majority which is a bit unfair. And was maybe the bit that got you the flack.
Maybe you meant the majority of those doing this, not the majority of racing bike folk doing it.
It is the case in my experience that the vast majority of close pass offendors ARE those who see themselves as speed merchants.
Close passes in london are pretty common in my experience.
No bell.
Some just say something when they are actually alongside you/in your ear - if they think this is of any use at all they need to stop and think. It's more likely to make me jump and may cause a crash in itself. And it is so stupid that, yes, one can't help but wonder if some do it with a sense of pathetic triumphalism that they are passing you. It's effectively the same as the passenger in a car leaning out and shouting OY in your ear. Whereas the vast majority of car drivers wanting to let you know they are there just give a short friendly peep when they are well behind you.
I actually apologised to one guy once - I thought I'd swerved towards/almost into him. We could have both ended up floored.
Of course I hadn't - I'd just looked over my shoulder for some reason and found him right alongside me. Maybe the look had made me move out by a centimetre, or maybe not. So up the road it occurred to me that he was a twat.
On catching up with some close pass merchant I did ask him whether he had considered a bell - the smug jerk said he couldn't find one that matched/was worthy of his bike.
In London I am particularly wary of cyclists sitting behind me in case they do the jerk squared maneoevre and try to come through on the inside.
Mostly this junk happens in London but I do sometimes get it from roadies and chain gangs in the lanes.
So, in short, ride like a good car driver.
Come past on the outside giving fellow cyclists a wide berth.
Ping a bell when you are behind.
Don't suddenly shout/whisper in/nibble on my ear.