Golden example or greedy landlords killing their golden goose.
Where I live all shopping centers in the town have the same fees for parking, CHF 1 for the first hour then CHF ½ for every half hour. You can pay with an app, for example https://easypark.ch, or by cash at a central parking meter by the entrance which accepts credit cards, too, and even returns change.
It's not really a joy but acceptable.
Charging for parking, then, is nonsensical. It's a cost imposed on your business just like the rent.
You could try to recover your rent/land costs by charging a flat fee for people to enter your shop on foot. Why not? Well, because no-one will come any more.
I've never seen a grocery store with a parking garage (opposed to a parking lot) that wasn't in a city. If the grocery store has a parking garage instead of a parking lot, then it is almost certainly in an urban area and public transit and is within walking distance of many residences and businesses.
This is in fact the case for the particular Trader Joe's in question. Look up "Trader Joes’s at Hollywood and Vine". That neighborhood is easily walkable, has at least some public transit, and their parking garage is within easy walking distance of numerous other businesses.