Should be marketed and sold with an asterisk, however, explaining the true measurements.
Anybody that buys one already knows, or will as soon as they measure it. I’ve actually gone to the tool department in a store and borrowed a tape to measure stuff I was selecting (not dimensional lumber). Labeling it would be on a par with having to label a knife “sharp” (which they probably do, but that’s no reason to propagate the stupid).
No. You would be buying into it. It’s called dimensional lumber. All dimensional lumber is referred to as a size that it is not.
Since actual 2X4’s are not available, the real size just flat does not matter. If the user isn’t smart enough to either know or use a real live tape measure, it’s their problem.
Either Lowes or Home Depot does put the actual size on their tags around here - might be both.