And that's before you get to other problems, like the potential blindness of the veteran. I know Assassin's Creed very well, but that may blind me to mechanics that I understand deeply, but are actually off-putting or obtuse to a neophyte player. We try, when the time allows, to offer dual reviews, like this Dark Souls II: Scholar of the First Sin review.  

It allowed a veteran like Bob to offer his perspective and a newcomer like myself to provide a different look at the game. If I could do dual reviews for every game, I would, but it's not feasible. Regardless, opinions and perspectives from those who are an outsider to a specific genre or unfamiliar with a franchise can still provide value to a reader. (Not necessarily reviews in that case.) 

Then there's critique. Depending on what you're actually critiquing, you should have a deep understanding of facets of that work. If you're critiquing Destiny 2's gunplay or Assassin's Creed's movement mechanics, then you should have a more than cursory understanding of those mechanics, so you can clearly state why they do or do not work. 

If I'm focused on a game's aesthetics or narrative though, then play becomes secondary at times. Play is a part of the narrative being told, but it's more useful in my critique to have an understanding of proper storytelling and current story trends in other entertainment media. Critique leans towards having literary merit and illuminating some facet of a work, while a simple product review seeks to tell you what work is and if you should purchase it. On USgamer, Caty leans more towards critique for example, I generally write reviews on the "product" side.  

Which is to say, all that comprises video game coverage and games journalism is complex. (Yeah, YouTubers and Twitch streamers are a part of this, though their mediums dictate different issues and constraints.) Should a reviewer be good at the game they're reviewing? As I stated before, I lean towards "Yes", but reviews aren't one single thing (product review or artistic critique) and resources don't always allow for a person that has a deep understanding or a franchise or genre. 

You can cringe about Dean Takahashi struggling through Cuphead. That's fine. But he's not a reviewer and he does his job as a reporter on the business side of games quite well. And he's also not me. He's not Jeff Grubb, Kat Bailey, Austin Walker, Danny O'Dwyer, Heather Alexandra, or any number journalists and critics working in the industry today. Games journalism has issues, but trying to make some larger point about it from a single video is odd and perplexing. There's no conspiracy there. We don't hate games. Sometimes we just have differing opinions, perspectives, and abilities.  

I hope that I can provide you with what you need, but I understand if that's not the case. I'm a generalist that has to cover a wide variety of games; I can talk about Final Fantasy XIV, but if your litmus test coverage requires bleeding edge Savage clears from me, I'm not going to be able to help you. And that's not a problem, because there's folks out there who do just that.