So why do people always expect me to gank mid when I'm split-pushing?

So in my last fight, I wanted to jungle with . But then I realized that I need some momentum going first, so I farmed top to gain some levels and a few items. thought that I was his laning partner until I started farming jungle as both sides started fighting each other in mid. For an while everything was fine until my team thought that we had no jungler. I announced that I was it. And then they were asking if I had Smite. I told them no, I have no idea what it was. And then they called me an noob (to be honest, that's normal for me.) and asked me to gank mid. I was too busy farming to care, so I didn't and started split-pushing to help carry the game. Team was not happy. To add more fuel to the fire, when I did help stall top, he wasn't happy that I was killing the minions with my critical hits.

What's wrong with me going off on my own to farm and staying away from teamfights? I know Tryn is powerful enough to defy being killed, but I prefer to win the game, rather than pad my KDA ratio.