I'm pretty sure he's talking about the words you post and the way that people perceive them. He is not the first person to talk about the proxmox team's "attitude", in fact I was just having a conversation with a colleague the other day about proxmox and he said "Yeah, the product is great, but the people who develop it are incredibly rude. If that's the way they communicate in public, imagine how rude they will be when they already have your money." I played the role of apologist, and tried to attribute it to cultural and language differences, but he wasn't buying it.
If you were only doing an open source project, and had no financial interest in this, you would have no motivation to present a more considered public persona.
However, you are attempting to profit from proxmox (rightfully so, I might add), so it would seem to behoove you to have a little more tact and communicate a little more politely. Of course, it's your business, and you should run it how you see fit.
Consider pfsense. Very similar situation: a company organizing open source software into an easily used, easily configured package, so they can ultimately profit from the support of it. Yet, they have a completely different attitude, and a much stronger community involvement as a result.
I don't think he's asking you to "work for him for free". You guys are the developers of this product. He's not asking for some obscure feature. You seem to forget that one of the most popular uses for virtualization is to allow you to take legacy systems and abstract them from the hardware, so the idea that because "windows 2003 is almost EOL", people shouldn't have a need to attach a floppy drive to a virtual machine, is pretty narrow-minded. I was in a shop the other day that had a stack of Windows NT VM's running (vmware).
Just some food for thought.