Genuine is a broad term that encompasses all levels of quality, just like saying plastic or steel or wood...broad categories that can vary a lot. The idea that it's some specifically bad leather comes from the mostly correct assumption that when they don't give more info then you can assume low quality. Like if you see a sticker that or advertisement that says "real beef"...it's probably a good bet they're not giving you a cut of prime beef, but that change the fact that a prime cut of A5 wagyu is also still "real beef"...
It's a broad term not a specific one...and the other terms bandied about are also much broader than people assume and can also be pretty low quantity.
People and articles repeat that leather comes in these specific grades: genuine, top grain and full grain.
But it’s simply not true terms are inclusive...all leather is genuine, everything that's not suede is top grain and full grain is unsanded top grain.
It annoys me immensely that all the articles call these terms "grades" because most people think of grading as taking objective measures that would be the same regardless of the source: The purity of metals, amount of marbling in beef, octane in gas, etc...but leather quality and price is going to vary by tannery more than these factors and there are thousands of tanneries all over the world. Those terms talk about what is or isn't done to a leather's surface mechanically (splitting and sanding), nothing more. They don't even tell you the animal, which can have a much bigger impact on quality!
If you're saying "genuine" specifically means a bad low quality leather then I'm sure you've seen the other side of that coin: "full grain is the absolute best/the highest grade"
Both of those things are 100% false. Cheap crappy full grain exists...and there are products stamped "genuine leather" made with high quality full grain.
Exhibit A: SB Foot Tannery is the largest by volume tannery in the USA they are full owned by Red Wing Boots and they use "Genuine leather" to refer generally to all their leather, even those that are explicitly full grain like Featherstone: https://imgur.com/a/Tdtbjge
Exhibit B: Horween tannery in Chicago is probably the most "famous" tannery in the world...just search "Horween" on or . This is Horween's explanation: https://www.thetanneryrow.com/leather101/understanding-leather-grains
Leather quality is much more nuanced than terms like genuine, top grain and full grain can tell you... there are hundreds of other factors that go into tanning "good leather"...it's a bit like judging something that has many components, like a computer, by one factor and nothing else. What would would happen if you just maxed out one component on your PC and left the rest at the lowest level? Ram, hard drive space, the CPU, the GPU, monitor, type of hard drive and dozens of other things come together to make a good machine...the same is true with good leather. Remember when people bought cameras based on megapixels? Any photographer will tell you that's not an accurate way to judge.
You can view the Full Grain>Top Grain>Genuine hierarchy as a "quick and dirty" way to pick quality if you're in a hurry and not spending a lot of cash on a leather item.
However, those terms do have actual meanings that don't always equate to good quality:
Full Grain is a leather that has only had the hair removed and hasn't been sanded (corrected).
Top Grain is a broader term that actually includes full grain: It's everything that's not suede, a split, this means that full grain is a type of top grain. However, when you see "top grain" in a product description chances are it's a leather that's been corrected (sanded). Nubuck is an example of a sanded leather (often used on the interior of watch straps and construction boots because it's more resilient to scratches), but so is a much beloved leather: Horween's Chromexcel (it's lightly corrected). The amount of correction can vary widely but once the sander hits it, it's no longer full grain.
Genuine Leather is, admittedly, a term found on lots of low quality leather. That's because the bar for "genuine" is extremely low: It just means real. To a tannery it's all genuine. When you read the description for "genuine" that many online articles give, they're actually describing a leather called a "finished split", which is a usually cheap quality suede that's been painted or coated to look like smooth leather. Despite what is often said, bonded leather is legally required to be clearly labeled as such, in theory, you shouldn't see it labeled "genuine leather."
Put simply:
Genuine=Not fake
Top Grain=Not suede
Full Grain=Not sanded
Anything beyond that is an assumption.
The gold standard for getting good leather is tannery and tannage...everything else is easily exploited by meeting the minimum definition of each.
