Most likely, Asians.
A few perhaps, but the whole thing sounds like an advertising gimmick for his restaurant. I doubt he'll sell much cat or dog, except to the occasional Pole who's thrill seeking, if at all.
I hope he is honest about what is going into his meals, too. I wouldn't want to go someplace, thinking I am eating pork and have it be a dog or a cat. That's another thing that concerns me about this. Product mislabeling. If he can do it, who knows who else is doing it.
Yes. there was a problem a few years ago near Piaseczno, very well publicised at the time. A place who supply Sajgonki to Vietnamese bars were using cat and dog. They were prosecuted for it.
dogs eat their own poop. so if you want that extra zing in your diet,, lol go for it.
As good a reason as any to avoid it!