I was sent to an early age neutering day long seminar by the vet I worked for. What I learned there, was that the younger vets were more inquisitive and open to the idea. The older ones were not going to change their thoughts on it. This is of course a generalization, there may have been vets that did not verbalize their opinions, so I would not know which way they were leaning. The one vet that stood out for me, though, was the older gentleman that stood up and quite loudly and angrily asked why anyone in their right mind would neuter a male animal. He felt there was no reason for it, he'd never done it, and would NOT alter a male animal in his clinic. He just spayed the females-they were the ones producing the offspring after all!
We too, were spaying pregnant 5-6 month old kittens. Not as commonly as the 7-8 month olds, but it happens. As a bonus, cats can become pregnant while nursing a litter, so you can have a cat with kittens that aren't old enough to find homes for that is gestating her next litter for you!