Those are the monitors HP aims at the enterprise. A lot of them have VGA only, and none of them have HDMI.
So in my organization, we have thousands of monitors that would require an adapter at minimum and maybe a couple dozen floating around that were special ordered one-offs that might have HDMI built-in.
Yea, what kind of display made since 2005 doesn't support hdmi (note: dvi -> hdmi is really easy and readily available)? Analog video died in 2001, and only persists in corporate America, and it is so horribly outdated broken and crappy I can't fathom wasting development effort to get a vga port or adapter working.
That's not a problem for anybody else. It's practically a non-issue.