when i got my ears pierced it was completely painless.
true, a cat could get it caught on something... but gillions of animals have pierced tags hanging off of their ears and other parts and bulls have this huge ring in their nose...
if there is a law created, fine... wise people make informed laws. if they are let go scott free that would be a problem too... there should be regulation to make sure that the animals don't suffer and can learn to cope with their new attachment.
You have to think about the animals though, and the 'jewelery' used. On a two pound cat, a 14g piece of jewellery will act as a wire/cheese cutter and just slice through the body part with ANY trauma at all. On a cow which was a thousand pounds give or take, with a THICK piece of plastic through it's ear, it can take a lot of crap before it gets pulled out. Also look at the habits of the animals. Cats roll around, squeeze through tight places, rub themselves around on things, play with other cats, and dogs etc... Where as cows, graze, lay in mud, maybe rub their butt on a fence, etc... It's completely different.
And if someone had so many cats, and they needed to be tagged to be I.D'd then that would be cool. But with proper identification tags, it's not as bad as using human grade jewellery.
So you can't really compare the two.
As for bulls with bullrings, lots are installed by vets, which pierce the septum, and insert a ring. Also, alot of people just use temporary nose rings on cattle, they clip on to the septum and dont harm the cattle in anyway, other than a slight discomfort for the first few minutes. And bullrings are not as common as you think.
They are used to control the bull, or cattle from harming humans. Bulls become enraged, and not only can they kill, but they will maul you if they feel the need to. They can be highly unpredictable, that is why caution must be taken with bulls.
Again, if kittens regularly killed people, and could be controlled by having nose rings installed, then you could compare that to this, but again, it's not relative.
It just bugs me when people in general compare apples to oranges, or fashion to function in this case, because if people really cared so much about this stuff, then there would be laws on treating slaughter house animals.
People can preach all they want about animal cruelty, but we can't help but be hypocrites.