This certainly wasn't a trademark issue. Trader vs Pirate. There was no question this store wasn't run by Trader Joes/Aldi North. They were buying in bulk to stock a store where they couldn't normally get the goods. Reselling should be 100% A-OK. Any trademarks go along with the products. And as far as I would guess, the grocer certainly wasn't tampering with anything - if (s)he was, they'd go out of business quick.
This is just normal SLAPP-style punitive legal actions that a large monied corporation can do to stop the little guy from doing legal behaviors that they don't like.