I think they were referring to nineplay's post, which was the GP of the post that replied to you. It gets pretty confusing, I guess pointers are hard even in natural language.
nineplay's post seemed to me to suggest that they believe that jaywalking being illegal is in itself a way to deal with the externalities of the car culture - it seems they are happy with jaywalking being illegal. I would guess that is why they also got the down votes.
Your reply seems to be written as if you thought nineplay was praising people making jaywalking not illegal, which I believe is the wrong reading of their post.
One of the ways we recognize the externalities of our automotive culture is by making jaywalking illegal.