It is a brief overflexion, and it helps to supple the horse and build muscle. I have no problem with it when it is used correctly
It's the people that take it to the extreme that makes it "bad."
Here's a quote from another thread I read somewhere else:
The main aim of all those employing this method of lowering and curling the head and neck of the horse is said to be to get the horse to raise the back and swing it. For the horse to develop the backmusles correctly they need to be working in a relaxed state and not a shortened cramped state, like some horses start out the riding session.
By bending the neck down, the back is bent up, and by tightening the abdominal muscles the back arches like a bow. This raises the back, relaxes the back muscles and the back starts to 'work'.
To a certain extent this is the truth, at least in a laboratory environment, experimented on the carcasses of dead horses where rubber bands have replaced the muscles' traction.
This is all mechanically doable and quite simple physics
.... and I'm sorry, but you can find almost anything on the internet, so quoting a website that says that it is evil doesn't sway me one bit. I heard about Rollkur as being a bad thing, but I really thought about it and did some reading and came to the conclusion.
Koomy, that webiste you posted has some pretty convincing arguments, but so does this website: http://www.carpenoctem.tv/cons/di.html
Does anyone remember the House Hippo commercial on TV? Just as with TV, you can't believe everything you read on the internet.
By the way, I'm not saying that you're blindly following this, but I read the exact same stuff as you guys - I was introduced to the Rollkur in the same negative fashion that you guys are - but I thought about it - and realized it actually might be a good idea if used properly.
Have any of you ever done Yoga? Remember seeing the pictures of the people bent in positions you never thought you'd get in, and if you ever tried them that day, you'd have hurt yourself? Well, months later you can do those positions... why? Because your muscles have been trained to - and most Yoga positions include over-flexion, followed by relaxation and letting your body stretch out.