While I totally agree that the rider here comes across as an aggro asshole, cyclists ARE allowed to ride on sidewalks in Maple Ridge, mostly because cycling infrastructure in the 'city' is brutal.
It doesn't seem like this person likes riding at all though, and her anger rage carries over into everything she posts. Plus, why the hell would you go down to the Seawall on a sunny day and expect anything but what she got (tourists wandering all over, gorbs on rental bikes, people going the wrong way, etc. etc.)?
I agree with others about the fingering // swearing at other people thing too. The last time I fingered someone on my bike (mid-1990s), I was commuting in Victoria and the recipient floored it a couple blocks ahead of me, parked his car, and then tried to clothesline me as I rode by. I had fingered him because he hit me with his truck's mirror.
"It's, like, so much fun."