Why can't roadies turn corners?

How hard can it be to make a 180o turn on a flat tar road around a witches hat? Pretty bloody hard, judging by some of the efforts i witnessed today in my comeback race. I don't know how many times I nearly ran up the back of other riders as they braked to snail's pace to get around the deadly orange cone. I suppose the road is only about 50 feet wide there, you gotta be careful! By the last lap I'd got it worked out, and went around near the front and got away with Col and Neil to try and chase down the two breakaways, coming up just short. 4th place in B grade in my first road race for 5 years will do me though.