I have no idea whether there are any regulations in the US regarding this, but nearly every chain store that sells grocery products also lists prices normalized to some product-relevant unit. These prices are on the shelves, directly next to the actual price, often in another color.

That is the case in the U.S. as well. Although I've seen unit pricing of products in different sizes use different units (e.g. one product using ounces and the other quarts) that if not done deliberately to make comparison difficult still has that effect.

Not a problem with metric units.

Only if the density is close to that of water. A quick google search says that approximating 1g = 1ml would work for yogurt (1.04g/ml), but not for honey (1.40g/ml).

They don't mark out honey in different base units. Some things are sold by volume, but even yogurt is sold by mass. It's partially because packing density is rather variable between different sources/grades, and also not as easy to handle as weight (just add on top, and don't care about the shape of the contents of the bowl).

Wow, I didn't realize how different things were over there. In the US, stores automatically started doing this without the need for government to step in. Maybe it became compulsory in other states but it seems like a huge waste of time to pass a law relating to this

At least here in Belgium, I do not remember there being consistent and uniform unit pricing before the directive was issued in 1998. From my point of view, the directive appears to have improved things so I would not characterize it as "a huge waste of time", quite the opposite.

Yes. And in the US, the units are still not uniform, so it means standing at each product for a few minutes with a calculator converting between units. It has wasted way more time than passing a law that requires the same units for each product.

Ask your grocery store to fix it or go to a different store in the area. In my area Kroger run stores have everything comparable, I would imagine their subsidiaries are equally as capable.