No, it is not a matter of having different opinions. Compare how many people successfully buy a puppy or dog from Pets4Homes to how many people have unfortunately been scammed. I'm sure you will find out that the latter is a tiny minority of people. A story pops up every now and then in a newspaper, that is all. It's certainly not on a big scale or every one in five sales, etc.
But just because it's a successful sale, doesn't mean it's not from a puppy farm. Lots of people are happy with their puppy farm dogs - doesn't mean it's not dodgy 
Of course someone buying a puppy which is being listed as being microchipped, KC registered, etc, but the puppy is in fact from a puppy farm is being scammed.
Lots of puppy farm puppies are KC registered and microchipped, though. Again, just because a puppy comes with all the paperwork, doesn't mean it's not dodgy.
There are cases of people IMO being silly and sending money to a puppy that never even existed. Why would anyone send money for something he/she has never seen before?
I agree, that is silly.
Puppy farms are always breeding, constantly breeding the same mother, etc. I didn't even bother to look up the other names you mentioned, but I fail to see how what you're describing is defined as a 'puppy farm'.
But that's simply not true. Lots of puppy farms are simply licensed to have numerous bitches, so once a bitch has had the KC limit of litters, it's sold/gotten rid of, and a new bitch is introduced in its place. Puppy farms aren't always bitches kept in dingy sheds for years on end.
Puppies from puppy farms are usually in disgusting states, the 'breeders' (I don't use that word to describe such vile people), better described as 'arseholes', breed a dog and don't care about the dog or the puppies and are just in it for the money.
Again, we clearly have very different definitions of what a puppy farm is, so we're not going to agree here.