It's really funny to me to just how much junk information there is in the coffee world and just how strongly people believe it. Even here on hackernews it seems. This is the exact sort of 'fact' that sounds good, and makes you feel like you know what you're talking about.
I'm a roaster. All coffee is sorted by size, or at least all quality coffee. It's necessary, not only for an even roast, but it's also an inherent part of green coffee processing. You have to screen and sort the beans to dry them.
The reason grocery coffee is bad is simple. They roast it until the oils come out and then the oils go rancid because it has been sitting on the shelf for the last 6 months getting to you. Even if it hasn't gone rancid (way more common than you'd guess), it's still stale and overroasted. Americans expect coffee to be dark, bitter, and cheap... And so that's what they get. But what you said isn't true. Even the crappiest bulk market roaster/reseller roasts by size and the blends after. They literally don't have a choice.
To be fair, a lot of the junk info comes from roasters keen on delineating themselves in any way in a saturated market. Taking words that are true for everyone and making them seem unique to your business is a sales tactic ad old as time.
https://espressocoffeeguide.com/gourmet-coffee/arabian-and-a...