Firstly, I'll make my posts as long or short as I please, thanks very much.
Secondly I didn't say anything was fact but that my extensive experience of this space leads me to a particular conclusion. I occupy these spaces almost every day, for considerable periods of time, and have done for the best part of a decade and I have two young children, so I feel fairly well qualified to comment.
I'm sorry about your experience with a mamil, I can only say experiences like this thankfully appear to be very rare. Anyway, the very occasional selfish actions of a tiny minority don't justify a law that makes little sense, diminishes well-being and actively discourages cycling.
There is no bandstand on Wandsworth Common so perhaps you're mixing up your parks... Clapham perhaps?
Just watch me get thousands of signatures on a petition and get this particular by-law changed.