I always find it weird that people (usually non-Americans) get so worked up about how US prices generally exclude taxes. I agree that it would be better and clearer if listed prices were tax-included. But they're usually not in the US. That's just how it is. Chill out, get over it, it's really not that big a deal.
This particular new law is not attempting to address that. Maybe it should. But maybe doing so would be biting off too much, and its sponsors believe it would never pass if they tried that.
The purpose of this law is much less ambitious, but that's fine. Incremental improvements are better than no improvements. I am pleased that now hotels can't spring daily "resort fees" on guests after they show up for their reservation. That sort of thing.
If you live in the United States, you know that a) listed prices rarely include tax, and b) for an annoyingly large number of things, you will be expected to add a tip. If you live here and don't know that, you are not particularly well-equipped to operate in the real world, and you should learn. If you don't live here but are visiting, it's unfortunate that you might not know about these quirks of American capitalism, but the law is not really aimed at you. Sorry, but our quality-of-life laws are tailored to people who live here first and foremost.
> If it's so easy to "know" the local tax rate for various things, why isn't it easy to label them?
It's not about being easy. It's about stupid psychological effects. If I list my price tax-inclusive, and my competitor lists theirs without the tax (but ultimately will charge the same price as I will), my competitor will get more business than I will. It's dumb, but that's human psychology for you.
> See the rest of the world, where even young kids can go shopping.
Young kids can shop here just as well. They just have an extra step to learn. They deal with it just fine; kids are smart and adaptable.