When I used to cycle with a club it became apparent that something that one rider deems bad enough to shout out or flip a finger at doesn't even register as an issue for another. Thankfully it was generally a pretty chilled bunch but there was the odd one who would use every opportunity to "take primary" and expect every road user to respect their 3m invisible sphere around their bike (while riding an inch off the bike in front, obviously).
I'm pretty chilled out on the bike but I have taken offence on three occasions. First was when I was physically put into the curb by a car. Second was some guy leaning out of the passenger window clapping yelling to "use the ******* cycle path"... There wasn't a cycle path, turned out he was referring to the metre wide pavement. Final time was when some no mark kid thought it would be funny to launch a McDonald's sauce pot at me as they drove past. That's over twenty something years so I'm not doing too bad. I'd loved to have had a cam on that last one as it was the only time I didn't manage to catch them up and have a chat.
The camerati and ding dongs like "Cycling Mikey" give the rest of us a bad name. I once got called out by another cyclist when I pulled up into a passing place and waved a following motorist past on narrow country road. "You don't need to do that you know. They have no right to pass you." Sure, but I'm having a leisurely ride, I'm not in the Giro d'Itallia so it has zero impact on me and they don't get held up for miles.
If only we could all get along but alas we are a tribal species. If we're not arguing about which team chases a bag of wind around the best or fighting over who has the best imaginary friend we're divided over how we get about. Pathetic really.