This isn't like a war correspondent showing bloody images of civilians being trapped between firing sides or starving emaciated children in some third world country. It's a couple guys having fun, discussing the differences between their film cameras and at one point dressing up in costume and interacting with the people they shoot.
The level of negative attention this has earned totally mystifies me. If you don't like Kai or Eric or both.. fine, don't watch them. If you don't like their method of shooting street [or street portraits].. then don't employ it. Each person has their own moral compass.
Some of the rants though, particularly on that youtube page.. are really over the top. Look at school shootings and hate crimes etc.. be upset about that. What does it matter that EK made someone pose for him rather than catching it 'naturally' from across the street. Compared to all the rest it's kind of petty and unimportant.