Toribash
Going to go out on a limb here and guess that it's because there are less linux users, hence a smaller priority.
because linux sucks.

jkjk. Basically what Odlov said. Not many people using linux, so demand for linux updates is rather low. While, PC and Mac demand is significantly higher. Thus, version updated are focussed around the PC and followed closely by the Mac.
[T3AL][Fish][o7]
My name's Mr. Cupcake.
Well, this computer dual-boots both Windows XP and Ubuntu 10.04, and when I run Toribash from Linux, I get a +9 FPS boost :/
that sounded so nerdy, good job. liek nerm and olov said, its just less of a priority. i dont see how 9 fps really matter unless your normal fps is under 20, i run just fine at 20-30 fps

It's because hampa lost the guy who compiles the new versions for linux. He's trying to do it himself now, apparently.
he lost him? like. he cant find him? lol.... ok... so yeah. sry but linux is gna be behind for a while i'm guessing...
[T3AL][Fish][o7]
My name's Mr. Cupcake.
Yeah, when I was dual booting I ran it in WINE. Got some crazy high FPS number, but it looked weird as hell, less fluid than it does on windows. With a small company like Nabi though they have to put their priority on the OS that is most common, sadly Linux will most likely always be 3rd in that situation.
Organisation of Awesome: Member.
I've never had any problems running in Wine, and it generally runs better & has less bugs than the Linux releases.

<Erf> SkulFuk: gf just made a toilet sniffing joke at me
<Erf> i think
<Erf> i think i hate you