Excuse me? So news outlets can't have opinion pieces? The start of the article actually jokes about doing an entirely objective list and here you are demanding one. It's quite impossible to do something like that when simply saying that a game is or isn't an RPG is subjective!
They're authority is that they play a bunch of games. That's it. Take a half dozen of us and we've got just as much authority. What's more, if you ask them again next year then the chances are good that the list will change - and I don't just mean to accommodate new games. In fact, PC Gamer does a top 100 every few years and games move around wildly.
I didn't say they can't have opinion pieces, let's face it, most news articles are opinion pieces, I said that a top 50 list can't be classed as an opinion piece, because it's the same presentation concept as Game of the Year, or review score, or handing out awards. Awards are decided by opinion, but the giving of the award is so entrenched in inevitable reaction that there has to be some sensible criteria for the award, otherwise it's a laughing stock.
So these guys preempt the laughing stock by being oh so clever and mocking their own pretense that this is in some way a newsworthy article instead of at least trying to put some form of basis to their reasoning beyond personal opinion (such as the reasons I list plus more alternatives). Wow, it's like they know it's all bullshit... but do it anyway... when the really cool thing to do would be to not play the bullshit game in the first place.
If something is impossible then don't do it... find a different way to communicate what you want to communicate. Also, definitions of RPG might vary, but there's very few games that are so borderline as to be completely uncategorisable - because most people who make RPGs start out by making their game RPG-like and apply a descriptor to the game which tells you its an RPG - because they want to sell it to RPG fans - who will notice if it's way way way off being an RPG.
Their authority is that they are professional journalists who command a very wide audience. Their article is presented as a group of people who play a bunch of games, because they want to associate themselves with being the little guys and are scared of patronising their audience which is mostly made up morons who think they are respectable journalists.
No, half a dozen of us would not make the same authority, we are not paid, have no qualifications and, most importantly, do not command a wide readership. Every single person here could rip the piss out of a random AAA game, but if RPS gives it 10/10 then it will sell 100 times better than if we all praise a AAA game while RPS give it 1/10.
I don't care how often they change the list nor whether other gaming 'magazines' are equally inept, that has no impact whatsoever on my point or any of the points I've made.