I don't see what's the big deal, it's always been like this, ever since Vista. If you buy a business machine running Vista, you have the option to downgrade back to XP. It's the same thing now, get a business machine running Win 8 and have the option to downgrade back to Win 7. IMHO, HP don't want consumers PC to have the option to downgrade (due to drivers), is because of support.
It's like a person building a PC for their friend with Win7 installed. His friend decided to install XP himself and then starts calling, asking hey why this don't work or that don't work. For the guy who build it, will he have the time to find out what the heck is going on and why it doesn't work? The initial OS was Win7 and everything works before he installed XP.
If a person was to buy a consumer based PC with Win8 and HP don't have drivers for that, they can still find it, not from HP itself, but from the website for the individual components.