[quotemsg=19621127,0,2452295]I guess this means they are confidant in their PC version. (optimistic)[/quotemsg]
It's based on Doom 2016's engine, so they've already got a big head start on making it work well on PC. Probably just not ready for showtime yet, and instead of making a PC demo, their focusing those efforts on making the game run properly. Which is often a choice that needs to be made in the industry today, making a demo or reducing Day 1 bugs. One of the many reasons you don't see that many demos these days.
Console demos are easy, because there's no hardware variation. If it works on one PS4, it'll work on them all, great, ship it. PC is obviously more complicated. Who knows, maybe it's not working great on a particular brand of GPUs right now or something and they'd rather not ship a demo that demonstrates that.