What if a competitor of companyX wants to slander companyX so that the customers avoided them and went to his/her company? How would you check the truthfulness of the complaint and who would be willing to do the checking and take responsibility?
I read the other thread after this one about giving a special place on the forum for such complaints, and I agree there should not be one. If someone has a problem with a company, then start a single thread.
As for company x saying negatives about company y, it's an anonymous forum.....lies are spewed on forums all the time. People who read things on forums need to take the info with a grain of salt.....plus, if someone is giving their account of the type of service they rec'd from a company, it would be very difficult for a company to dispell. It's not illegal to share an opinion.
Now if someone states that company x is involved in laundering money to terrorists, mobsters, etc....something which can be proven, then I could see your point, but that would go on the individual.