Yeesh... ok, here's the thing. The code that went into creating the creatures in the creatures series is actually really comprehensive, far more comprehensive that a lot of people ever realise.
In fact I'd say that the intelligence of the creatures in the creatures series is approaching, but not quite in the region of my dogs or cats or other household animals (keeping in mind that the world the creatures reside in is far, far, simpler than the one we reside in, they don't have to worry about lots of complex spacial recognition issues and such). They do in fact act a hell of a lot like ordinary pets (barring the occasional glitch in the system), to the extent where I feel if you stripped my dog down psychologically and placed it in the creature's world, it would sometimes get a little hard to distinguish... if that makes sense.
They're also very good at tickling people's empathy bone, simply put, norns are designed to be very cute and easy to empathise with. Given this, it's actually very easy to see how people could get very worked up about creatures being abused the same way they get worked up about dogs being horribly abused.
While I recognise that the existence of a creature is different from the existence of my dog (I can't pause, save or reload my dog's life for example), I have to admit, I still find it more than a little bit off-putting that someone would go around trying abuse a creature, even if it is just for educational purposes.
I'm not saying that this reaction wasn't a bit ridiculous, and I get that a lot of people would have a lot of trouble understanding this, especially if you're the type to assign pretty much no significant value to the life of an animal, but I am saying that I honestly can empathise with that kind of position.