Pedestrians can walk wherever they like on a shared path, so his 'keep left' admonishment was somewhat out of order. In fact pedestrians retain the right to walk anywhere on a segregated path (i.e the ones with a painted solid line down the middle, a la London Fields) as well.
Ah, I was pedestrianised at the time, not riding. Hence getting irritated.
Will remember your crotch spit tip though.