What technical reasons are those? I remember hearing this when I was 15 or so, as part of a "Unreal Sux"/"No Quake Sux" debate. (I was observing) It didn't make any sense to me then, nor does it now, how a 3d graphics engine could be limited in color palette to just, say, brown. And I distinctly remember the color blue showing up in that game anyway...

I could be mis-remembering, but I think Quake started out with a software renderer that operated in VGA mode. So the game has a 256 color palette.

You are correct. Quake was before mainstream 3d accelerators and only had a 256 color palette.

Original quake palette: http://www.gamers.org/dEngine/images/quakepal.gif