Okay fair enough. It is true for one person to blame others than admitting they are the greatest common denominator.
Look, I may look like an Elf that thinks I’m good enough to get into groups easily as much so that I want to get into Sargeras’ pants… and cause sundering of the world.
Nah, I’m just another player. A deeps player. If a sweatlord wants to look me up for results, then that’s the kind of group that want results over everything else that I am not sure if I even want to be part of. Especially if it is a pug. But hey… if it means of progging… I guess I can go through with that procedure.
Conclusion? I am not perfect. Hell, I don’t think I am good. Yet I got 2.1k rating on my Warlock through BG Blitz and even I know that’s mostly luck of the draw and I STILL don’t like pugging.
Okay so let’s try making my own M+ group for example! I have a key and 1 of my friend is online who is a healer! Bet! So we have to pug… 2 deeps and a tank. After all, to get good at the game is to play it… right? 
One from Azralon… Pass. Ragnaros… Pass. Oh, here is a tank from Eredar like you! And we found another two from Area 52 with one of them have Lust/Hero. Cool! Bet! Depending on how high the key is, the adverse the effect of pugging. For instance, if you are running like… let’s say +15 (not Lemix) and the tank dies on pull… and then leaves… and my key is depleted.
Okay… so my key is depleted for pugging a poor tank. So it’s +14 now since I don’t have KSH.
Did this again… and now it’s +13. AND SOME HOW, as easily +13 sounds… we didn’t even time it so it’s +12.
You can see after not just 1 bad experience (not just another player but gameplay design that can compound) can lower someone’s patience with pugs a bit. It adds up. The more this happens, the less you are tolerable with other people that would devolve you into a League of Legends player.
This is a hypothetical example but if a couple of bad seeds just deters me to progress and require a lot of patience to set things up… I just conclude that maybe the M+ experience isn’t for me and should be done with friends and guildies. I just don’t think it is designed for pugs based on this experience alone that maybe you think it’s hyperbole.
And I’m sure that not only just Forums but Reddit (and perhaps other places that we know of… maybe MMOchampion? Who even uses that?) also have some fair share of pugging complaints. Pugging just… sucks. IT SUCKS. It is fair enough to tell someone to make their own group, friends and guildies in all…
But asking a question of how someone playing their character affecting you in this whole pugging ecosystem or any content that require other players is a bit silly to me. Even more so since majority of M+ & PvP are done through pugging too! Which is why we are here in this conversation! 