Her range is 550, which is average ADC range... The first time I played her I thought she would have like 500 or 525 range since everyone kept saying how unsafe her laning phase is and how she has pretty short range. Is this just something that people say in order to defend Vayne and prevent nerfs hitting her?
Vayne has "short range" because she has no abilities which allow her to affect enemies outside of her autoattack range.
WR
QR
QR
ER
QWR
QR
WR
Q
QER
QWR (Targeting a minion)
QR (Bounce Q off a minion)
Q
QW
QE
QER
and 
are the only other ADCs who can't affect enemies outside of their autoattack range and both have abilities which can extend their autoattack range significantly.
She has nothing but that 550 range to fight from. Compared to other people with that range, they have some sort of extra distance poke or HUGE gap closers, or both.
Other ADCs with 550 range have some sort of poke spells to compensate. Literally all of them. Don't believe me? Look it up. Sivir has a boomerang, Graves has Buckshot, etc etc etc.
However, her laning phase is weak, sure, but SAFE. She can safely farm because of her mobility and self peel.
Vayne has nothing but a very small gap-closer to do anything outside of her AA range. Additionally, she has no way to increase her AA range (unlike Jinx, another hypercarry ADC). Due to this, she can get focused really easily in a fight and wiped out before she can destroy the enemies.
because auto attack range isnt the only thing that matters for ADCs their spells matter also shes the only ADC with average or worse range than most and doesnt have spells to help out
