It's a big shame. I do dual-boot with Windows, but only because I cannot let go of FFXI. I keep getting very tempted to buy UT3, since I still play both UT and UT2004 today - that decision would be so much easier if they released a Linux client. I do not like dual-booting, it's a pain having to switch between OS's, so being able to play previous UT's without having to log back into Windows is great.
I'm not overly surprised about Epic's reaction, they've been the centre of some pretty shoddy PR handling over the past 2 years, Mark Rein especially has a habit of speaking without considering the consequences and how it will be taken. The guy just has no idea about how to approach PR. Knowing Rein's past record, he probably didn't mean to describe the Linux client as a 'pet project' in the frankly insulting way it came across, it's just so typical of Mark to say something like that, but not actually mean it quite like that.
Here's another conspiracy theory to throw into the works, Epic is one of the key players in the recently established 'PC Gaming Alliance', an alliance that seems to be very Windows-centric.