Why do we now have to identify crosswalks, stairs, buses, fire hydrants and more before this site will submit?

To prove that you are not a robot. It's annoying at first, but then you won't have to do it everytime.

To make sure we aren't bots.

Every answer is a bit too much,

They can charge more for advertising by showing the advertisers their ads will be seen by real people. They'll say it's for the benefit of the users to limit backlash.

There were bots at one point advertising and abusing the format here.