The USA with 350 million people has a tiny, tiny percentage of folks that give gunowners a bad name. Walmart has a tiny, tiny percentage of its 2 million employees that make stupid decisions.
Seems you could find a better reason to boycott them, if that's your decision, than the referenced issue.

Imagine your grave on a windy winter night. You've been dead for 70 years.
It's been 50 since a visitor last paused at your tombstone.....
Now explain why you're in a pissy mood today.