jbbeats had an interesting point before he fell into personal attacks so I will express it here with less vitriol.
Jailbreaking is explicitly not an intended use of the product, and a manufacturer shouldn't be expected to provide any support whatsoever to something which the explicitly do not intend as a use. There may be all sorts of unintended consequences to jailbreaking and its unfair to expect a manufacturer to have the resources to think of every possible use case.
To take a ridiculous example (without copying jbbeats) if you choose to cut your hair with a lawnmower, you should not be able to complain that the lawnmower manufacturer didn't make it easier for you to swap out the blades for ones that barbers use instead of the cutting grass variety. That I think would be an unreasonable burden to put on the manufacturer.
There also may be unintended consequences in the basic operations of the machine if it is used in a different use case. For example, maybe hair grease could acccumulate overtime to make the lawnmower dangerous overtime. Perhaps a rubber guard would prevent this. Now the lawnmower manufacturer is having to support optional rubber guards for each range of lawnmowers for those few people intending to cut their hair with it.
While I share your desire to make jailbreaking easier, I don't think a law is the right way to do this.