As a large bird owner, I search Youtube often looking for thoughtful content made by someone with large birds. I've had birds for decades so I'm looking for info beyond beginner. I have yet to find it. I have found several reptile channels/youtubers I enjoy, even though I don't own reptiles. Marlene's channel is clickbait and entertainment, not quality psittacine info.
I had no idea members of this forum hated YouTubers so much.
This is a generalization. We can be reactive here, as you say, because most of us genuinely love parrots and are protective of them. When we perceive an impropriety towards parrots, we don't let it go.
Her parrot food is a blend of Tops pellets and healthier seeds and grains. What’s wrong with that?
Nothing at all. She's making a buck off her notoriety. I would, too, if TOPs asked me. I wouldn't have put that many grains in a diet designed for most pet parrots, which are sedentary compared to their wild cousins, but that's just me.
Marlene is in no way a hoarder. All of her parrots are rescues except for one.
Hoarding has nothing to do with rescue. It's having too many animals, more than you can care for. You could rescue a bird and be a hoarder. I'm not saying she is; I don't even know how many birds she has.
I have 2 problems with her. One, she "freed" an Amazon that was CLEARLY not feral. I notice you didn't address that point. Second, if you peruse the products she recommends as an Amazon influencer, they're not all great products for parrots. Other than those, I have no problem with her.