Mods aren't about "working". Mods are about being beaten in the head with a cactus until you leak delicious, cheesy intern fluids. Then, and only then, will the ringing begin to fade and you hear your own screams echoing back to you as you tumble down billy's infinite gullet.
You asked why.
Well, I can't make my own mods, or make older ones compatible, if I could I wouldn't be posting on here. It is about mods working or not 
