Hmmm, doesn't seem that way to me. The fact is there is a big hole in the Mac lineup. There is no Macintosh, any long that is upgradeable. It didn't feel to me like it was slamming Macs or trying to start an argument. Just highlighting an important point about the Mac offerings. As a Mac user it doesn't bother me to know that people are finding valuable options when there are no Macs that fit a particular need.
The inflammation comes from his tone. "So glad...Macs cannot be upgraded...kickass HP"
This is coming from someone with a top-end 5k iMac Retina on his desk, desperately wishing for a real upgradeable headless Mac with powerful consumer graphics. I, like OP and many other consumers, would pay handsomely for such a machine.
I agree with OP's intent, but his delivery is inflammatory. There are better ways to start a discussion about the gaps in Apple's desktop lineup rather than telling us you're "so glad" you didn't buy one. He's not really telling us anything except that he's glad he didn't purchase a computer that we all likely have, on a forum that we talk about such computers on. Useless.