lilmod: “Gourmet Glatt can post their prices online. They can not make a point of posting Season’s prices and comparing it to their own.”
DY: “Lashon hora is assur even if the listener will figure out the negative implication from information they didn’t specifically hear from the speaker. So, if a price comparison were assur, so would stating one price be assur, because at least some of the listeners already know (or will find out) the other.”
1. It’s not the same thing. First of all, there are different types of loshon hora. One of them is giving someone (negative) information they didn’t previously have. Another one is saying something in a negative way.
Stating that Shoprite charges 5$ for milk is not describing them in a negative way. If you say that Shoprite charges more for milk than Pathmark does, you have just described Shoprite in a negative fashion that may cause them to lose business, even if you didn’t give over any facts that the person didn’t already know.
2. some of the people you are speaking to may not have known that and it may not have been important enough to them to look into it (but once you tell them, they won’t shop there).
3. You are assuming that a) must be muttar because b) is muttar. Who says that b) is muttar? I happen to think the two cases are different as I wrote above and the fact that a) is assur doesn’t make b) assur, but if you think the two cases are the same, then maybe b) is also assur.