There are certainly loopholes for them, Walmart, and every other retailer. However, the $18 applies to over 100k jobs [1], so it's not meaningless.

I'm not saying that the labor market is cartel-free, but Amazon is legit a step up from Walmart (at 65+ P/E they can afford to be).

[1] https://www.cbsnews.com/news/amazon-18-dollars-hour-starting...