Why do people have to hate on kids?

My sister, BIL and their two toddler girls came to visit me for a week. On the second day, I took the girls to a bazaar to let the parents chill a little.

Arrived, bought pancakes and marshmellows and start eating. About 10 minutes later, a teenager from a nearby table and started yapping about how much SHE hates kids and then dips!

I just? Don't get it? They're 2 years old and haven't even looked towards you until you came up to ME.

I get some people think children are morally wrong or whatever but seriously?