Genre exploration: Glam and hair metal

I talked briefly about genres and sub-genres in metal and hard rock a few weeks ago. All I did was just scratch the surface because in order to figure this out we have to dive in quite a bit deeper. If we think about when did heavy metal start most people will point to the early 1970's and bands like Sabbath, Deep Purple, Zeppelin, Uriah Heep and others. Bands like Iron Maiden and Judas Priest might very well be direct descendants of those pioneers, but what about bands like Motley Crue and Ratt? Okay, here's where the guy in the denim jacket with the Slayer backpatch jumps up and says "hey, those aren't metal bands". Alright, then what kind of music are they playing? You could play it safe and use the term that makes these bands seem like safer, less rebellious cousins of metal and call them "hard rock". I may not argue using that term, but it is kind of general. So what if you call them glam? Well, then the classic rock/70's fan shakes their finger and says "no way, glam is bands like the New York Dolls, Slade and the Sweet not the MTV generation 80's bands". So what if I switch gears and say okay then the 80's bands like the Crue, Dokken, Poison and the like are hair metal. Okay, so now the 40 year old guy wearing his 1988 KIX tour shirt his swinging his arms around and cursing me for me putting down his music. It wasn't called hair metal in the 80's so why is it called that now? Fair point maybe. So if we accept that 70's bands like the New York Dolls and the like are glam then are they the only ones who can use that label? Now someone like Hanoi Rocks really did have a heavy early 70's glam sound despite the fact that their prime was in the 80's. Members of Motley Crue, G-n-R and others claimed influences from the likes of Sweet and early Alice Cooper even if the influences were not that apparent. So can there be a 70's and 80's glam? Would adding the decade to the label be too confusing? I don't think so, but you still get the 70's fans who think the 80's stuff was too fluffy and the 80's fans who think their music wasn't strongly linked to an older sound. Now to further confuse things you get 70's acts like Aerosmith and KISS who were glam in appearance for sure and both bands were hot again popularity-wise in the 80's. So were those two bands always glam or were they one thing in the 70's and did they onto a slightly different fad in the 80's? Your decision might be based on how much you like those bands. Now I really don't mean to muddy the waters on this topic and provide more questions than answers. However I think this one of those genres that's a little harder to define. I think hard rock works fine in describing those 80's bands although I am not opposed to glam if it is defined as 80's glam because I think it is separate enough from 70's glam which is different. I am not big on the hair metal label and don't think it works as well as the above labels. A few years ago I was involved a big discussion on a blog when someone called Roth-era Van Halen hair metal so I think that label has some holes to it as well. Feel free to add your thoughts on the topic or tell me to quit rambling and get back to doing reviews.