I wouldn't call that bashing. If you were looking to buy hosting for a website there would be hosting services that I will recommend and websites that I would warn my client to stay away from.
Doctors often do this with things that aren't healthy for us. I you are looking for a boat that floats, then I will warn you about a company that sells boats that don't float. In the same light, If you were looking to buy a boat that doesn't float, then I would single out that company again because it fits your needs.
I single things all the time for either good or bad services. There's a Taco Bell that has an 82 rating. So I tell people not to go the taco bell at that location. This is a much easier way to provide valuable information than to try to figure out which Taco Bell locations have good ratings. I don't know where my friend may be when they want to buy a taco, but if they are in the area of that one store with that low rating, then I tell them not to go to that one.
The one thing I rarely do is say that just because service is bad at one location that it's bad at all locations. I only do this with Walmart. If you want good technical customer service on computers then don't go to Walmart regardless of the location.
Walmart is good for other things, just not for good technical service on things like computers and tablets. They do some things good and that isn't one of them.