Why do my teammates always underestimate sivir?

I had couple of games in the last month that I've lost vs sivir, and there were games that i've won. The ones I've lost, almost everytime one of my teammates would say "How does the weakest adc in the game is so fed". now, honestly, she isn't weak! and no, I'm not saying that because she is probably THE "lcs fav adc", but because she is just legit strong adc. even after the nerfs she has an incredible scaling, she is getting stronger as the games goes on, if those people would've look on champion.gg statistics they would have seen that her win rate is getting higher the longer the match is.

The nerfs to her were fair, but she is still that late game very high aoe damage, that can really solo backdoor and win the game while you guys are doing baron.

I wish my teammates would acknowledge that... maybe then we could have played better... but my question is really, why do people think she is weak? or it's because of the elo im in (silver 4).