Vayne is squishy, she is feast or famine. If you are behind you are useless if you are ahead you're a nightmare. Most Vayne players will attribute them getting behind to their jungler not ganking for them enough their support not saving them enough top lane for not TPing down bot enough and mid for not calling mia's or roaming bot. They rarely will own up to their own mistakes, because even in a game a vayne is behind is the game drags out long enough, and Vayne gets enough gold split pushing by herself pouting like a kid.....she WILL buy items and reach her power spike, come back to a fight, and suddenly get a triple kill.
It's ego. The public view of Vayne (get ahead or die) encourages the toxic selfish mind set. If you're behind it shouldn't be your fault because you're adc your mechanics are perfect! It's like the guy that made the post to explain why junglers do and don't do what they do and don't do. Alot of people saw that as an excuse to play jungle and basically have a FAULTLESS role. No matter how bad a jungler is, they don't gank, or gank badly, no matter WHAT, a jungler can just pull up this thread that was made, and select and pick one or two excuses out of a list of otherwise VALID expainations and just repeat them in team chat, thus in their mind alieviating any responsibility.
It did worse for junglers then the OP thought it would help. They believed it would clear up confusion and help teams understand one another better but all it did was give trolls an excuse to keep trolling under the pretense of "Oh I'm jungling there is no wrong way to jungle not my fault you lost lane"
Nothing is the bad jungler's fault, and he'll blame the team for feeding when it's his fault he never ganked and enemies up 2 dragons and 10 kills and he'll use THAT as his excuse as to why he will conitnue to NOT gank.