I decide on toys for my GC and other children I buy for by their play value. I haven't seen the pooping flamingo, but seen lots of pooping toys. The Barbie that someone mentioned with the poop and scoop came with the Tanner pooping dog, and lots of little accessories, and was very good fun, and good value. Also taught cleaning up after your dog!
My girls had Tiny Tears drink and wet dolls - I can't see the harm in toys that have 'bodily functions'. We all pee and poo. Kids grow out of all this being funny.