slow down?

I'm really confused as to why people wandering around on the road in the middle of the night can have any authority to tell people to 'slow down'. I don't care if they have children with them. The speed limit is as it is, sometimes I'm going faster than it. This time I was going around an angled curve, so I was actually in fact going the speed limit. Needless to say, I had a few choice words for the lady, and then secondly a man standing in his driveway a block later who decided they had radar powers and somehow knew I was driving excessively fast. I suspect the somewhat inebriated state they were in affected their superhuman abilities, but I was not in the mood.