Meh. Maybe you've seen/experienced different things than me, but I don't really see this. He's been around longer than most, but he's less known to most than the current wave of whiskeytubers. He loves his ascots (which is pretty douchey), but other than that he seems like a pretty normal dude who just happened to make a career drinking whiskey. I'd do it if I could too.
As far as availability of products, again, he's got so much less influence than whiskeytubers that he barely moves the needle on availability. The only time of year he has any influence is now - when his year-end top 100 comes out. Even then though, the bottles on the list that are rare and allocated were already rare and allocated. The bottles that are more readily available usually stay pretty much that. Last year for example two Larceny batches made his top 10, but I still see those sitting on shelves to this day. The NBC batch he put at #4 last year is STILL available on their website (only place it's available). Most of his throughout the year reviews are behind his Patreon paywall and the available stuff is just him hanging out drinking a random whiskey with a random celeb.
The gripe most people have with him is that his list can be so off from everybody else's that there's a big belief that he promotes what he's paid to promote. Nobody has actually provided any actual evidence of that though. They site the Larceny batches in the top 10 last year as proof. Who knows though. I have both of those batches and they are damn good. Would they make my top 10 if I had access to everything he has? Who knows. The NBC batch def would. He doesn't include things like 13th Colony Double Oaked because of the controversy and usually doesn't include Van Winkle stuff because he doesn't think they are anywhere near as good as their premium would indicate. He doesn't include some finishes, like amburana, because he doesn't like it. He's very clear that this is his list and he likes to promote whiskeys who are doing different things and doing them well.
I take his list with a grain of salt like I do most of the whiskeytubers. I think they're interesting, but they're all just their opinions/palates. I may pursue a bottle on his or any list if I know it's available, but like I said most of the stuff on these lists is made allocated and mostly unavailable by the distilleries, not Minnick or any other whiskeytuber. Half the stuff on his lists usually isn't available in most markets because it's smaller distilleries, so you have to order online if available.
Hating Minnick or any of the other for their reviews and lists is like hating Michelin for their stars, James Beard for their awards, or hell even Yelp for providing reviews.