She's picked for her solo lane dominance. That is literally what she does best. LOTS of heroes can gank and secure kills, many as good or better than her. But they do not have her ability to not only hold but win a lane against ANY other hero in game, even being able to hold a lane vs 2 heroes in many cases. You are right, facts are a powerful argument, at least normally. Not sure why it doesn't work on you, is looking stupid REALLY preferable to acknowledging what everyone else already knows, that you are wrong?