In the GRRRRRRRRRRRRRIMDARK future, there is only war. And despair. And darkness. And edgyness. And then there's the Orkz, who merrily chuckle away as they beat someone to death with his own severed arm.
I like a great number of things about Orks, but none of them are why I like Orks. To be perfectly honest, I really just don't know. It just seems a natural fit. Although: I'd be lying if I said I didn't suspect it had a lot to do with the shenanigans.
I was into Warhammer Fantasy first. Getting into 40k I didn't initially like the Orks as they seemed out of place in the setting. But the personality and presence the writers gave them and the dialogues and quotes in the Dawn of War games sold me. Now I find the 40k Orks far more appealing than the Fantasy Orks. Like they are defying sci-fi/fantasy tropes to stay relevant in the 41st millennium.
Because they're fun dammit. Everyone else with their grimdarkness, its nice to just krump a few gits.