True, and I can honestly see the reasoning behind that. It sucks that people can't be trusted to alter the puppy when it is older and the dog has to get altered at an age when it's body needs it's hormones.
Fortunately a lot of giant breeds get pulled out of shelters by breed rescues or shelters contact breed rescues when a dog comes in and if it is an unaltered younger dog it may get the chance to mature longer and get the health benefits of a more breed appropriate altering. The large and giant breeds have more of a health risk by early altering.