Grindcore is a silly genre. Due to its underground status, bands can pretty much do anything they want. Bands such as Anal Cunt attempt to be as offensive as possible. Napalm Death holds the world record for shortest song (You Suffer is 1.316 seconds long). There are even themed bands like Milking the Goatmachine who, you guessed it, wear goat masks and sing about goats. And the fans love it. Also their vocalist is their drummer.
I have at times dabbled in grindcore, but it is not a genre for me. There's just something about having structure in songs that appeals to me. There are a few bands from grindcore fusion genres though that I do enjoy. Benighted, who I posted about a bit ago, Misery Index and Anaal Nathrakh are all deathgrind bands. It's the furiosity of grindcore combined with the structure of death metal.
While it is not a genre of metal, grindcore is still pretty metal. And by that I mean awesome. There is just so much fun to be had when the bands don't care about anything besides brutality.