they can be used in any manner you wish
That's not entirely true. There is a TOU, and it differs for different photographers, agencies, etc. Using them to scrap for yourself is generally just fine, the TOUs are usually more about commerial purposes, but I would urge everyone to know the TOU of any stock photos they use.
As for it bothering people, I have to agree with you, Col. Everyone scraps for their own purposes, and I don't think it's our place to judge that some scrapbooking is more valid than others. Yes, using photos that you have no permission to use is a whole other thing, but we're talking about stock photos here, and if that's what someone wants to scrap to further their creativity and abilities, then more power to them.
These sorts of topics have been coming up a lot on different boards, and I'd like to echo a sentiment posted by one of my favourite scrappers in one of those threads: there seems to be so much negativity to differing styles, what people scrap, how they scrap it, etc. and I'd love it if we all focused that energy on the many positive reasons we do this instead of worrying about what everyone else is doing. (not her exact words... my words, but same sorta idea)
Not trying to sound snarky myself here. I hope that's not how it comes off. It's just something I've been thinking about a lot for some time now.