I can see why some would argue a first heat is an incredibly moving experience for everyone.
Including the dog who for sure should gain depth of doggy world wisdom from it. But after the first heat, keep a dog in heat and not breed? WTF? Unless you want your dog female to be super duper vulnerable for no good reason, spay early. Breeding dogs and cats is TOTALLY unecessary. Spay and neuter your loved ones furry style.