I think the real trick there is to remember it's for stupid people. This is 75% of their diet that isn't the free choice hay they also suggest using. This is basically listed this way to stop people from feeding their pet rabbits buckets of treats.Also, it said 75% of their diet is pellets. What the heck.
It's also worth noting that lots of people feed pellet only diets, especially in meat rabbits. I won't say it's good for their long term health but it doesn't cause any sudden deaths.
When I had my lops all those years back the vet I was seeing (who was admittedly a BIT of a dingus) told me to feed timothy-based pellets and hay free choice (same instructions listed on the care sheet). Something high in fiber and low in protein like the fiber 3, the oxbow, or the kaytee forti-diet could easily be good for rabbit longevity. Even the House Rabbit Society suggests feeding timothy pellets at the same rate listed in the petsmart sheet.
This vet article suggests a similar, but lesser amount;
Vet tech article suggesting a diet that a high quality complete pellet could provide without hay;
There's really no room for nuance in those care sheets like "Your rabbit doesn't need pellets if you give them all these other things". They have to get the info out and into the customers brain quickly.