Why do people play suicide Singed??

So enemy top is Kassadin, jungle Nasus, and our top locks in suicide Singed, just feeding kills and assists to Kassadin or Nasus the whole time. Jungle Nasus must be bad at farming because Graves had double his CS at 20 minutes, but then Nasus comes back with 4 kills and suddenly has items and some damage. Kassadin doesn't even need an explanation. So I'm support, I'm actually keeping the enemy from scaling, and I'm like why are you suicide Singed-ing and dying to close the gap? Then Graves says I'm annoying for talking and proceeds to intentionally throw. Is this even a game...