That lance Hedrick video had a lot of good relevant info.
I’ll add that the definition of “light” changes as much as the definition of women’s pants sizes do. Its essentially “vanity sizing”, but for flavor. Most consumers, at the end of the day, want their coffee to taste exactly how they are used to, but they paradoxically also want to be having something “different” or “unique”. It’s why Hawaii is full of roasters selling $70 bags of coffee that taste the same as $8 grocery store bags.
Roasters have to weigh whether to give accurate info that will appeal to us nerds, or whether to aim for the general populace. There are probably many roasters who legitimately don’t know better, but I’d reckon many roasters are just making the economical choice.