As a life-long New Yorker (Manhattan and more recently Brooklyn) I just don't understand why anyone would ever ride a bike in NYC, period. I even stopped rollerblading in NYC when some asshole driving backwards (presumably to get a parking spot) nearly killed me and did knock me silly. I have a motorcycle license I got one summer when I had free time. I learned that cars and pedestrians are your enemy, and that you w…
Heh, just today I was biking down a hill in a segregated lane. Green lights ahead of me, all the way to the waterfront. Some guy in the crosswalk, going against the signal (I have green lights for several blocks), left to right across the street. I'm half a block away but I'm going downhill and going pretty fast. I yell, "Watch out!" He keeps moving, so I start to veer to the left to go around him to the left. THEN h…
In my country driving instruction emphasises the importance of anticipatory and cooperative driving. Anticipatory in this case means taking the high likelihood of further misbehaviour of the pedestrian into account, cooperative means reacting early so you don't further create risks by surprising traffic behind you if you need to come to a full stop later on.
This applies to bikes as well as anybody else on the road (including pedestrian). You should generally expect others to follow the rules but if there are indicators they won't (e.g. they're violating them or they're too young or appear confused/erratic) you should anticipate that they might create dangerous situations.
So, yes, the pedestrian was obviously and blatantly violating the rules but your description makes you sound equally reckless. If you were going so fast you couldn't slow down enough to mitigate the risk of a collision, you were going too damn fast. Going downhill doesn't mean you're allowed to go full speed, in fact it means quite the opposite.
EDIT: The most important takeaway is predictability. Traffic rules are 1/10ths about helping you and 9/10ths about helping other people. Bikes don't strictly need lights for visibility, for example, but riding with a light allows other people to actually see you in suboptimal conditions.