Funny that all of these arguments jack of the price of the non-Apple by building it out to the specs of the Apple - but nobody considers that some people might not need all the stuff that Apple includes in the bundle. ...or that some people might need stuff that Apple can't do.
The marketing page that you linked to is filled with BS. Whether or not you tried to make the point that the comparable HP system was cheaper, HP *clearly* is. "All the pros are moving to our system! Look at what we give you! That crappy Mac Pro is $3,000! Ours starts at $2,439!"....and then when you actually click to see what you're getting at that price point, it's equivalent to a workstation version of a barebones PC you'd pick up from Newegg.
"Some might not need all the stuff Apple includes"...You would have a point if actually buying the base config wasn't so close to the pricing of the base 4c Mac Pro. I mean, it's literally a waste of money when you factor in how much the extra $500 and change gets you. Also, it's my understanding that the Xenon chips don't have onboard graphics (although I could be wrong about that). If that's the case...you wouldn't even be able to boot the computer HP will sell you as its base machine. That's laughable.
"Or some people might need stuff Apple can't do"...which is why I mentioned the HP workstations are nice when you load them out. However, that wasn't the point you were making at first, nor was it the point of the marketing webpage HP has set up.
You're also sort of trying to play the "false equivalencies" card. The way you are talking about the HP makes it seem as if you don't believe the same kind of people are deciding between these two machines. "Oh, well, people who aren't well served by the Mac Pro would buy this". Well, HP clearly thinks otherwise, as they have set up this page to try and dissuade potential Mac Pro buyers with misleading pricing and configuration claims.
HP is just another entity attempting to tap into the internet rage when Apple removed internal expansion, except to actually buy a system comparable to the $2,999 Mac Pro, you need to spend a lot more. And they are so afraid of people figuring that out that they created a huge page full of misleading charts and price comparisons in order to get people's money.