If you value the status symbol of a Rolex (not I - I think they are tacky and ugly - sorry) fakes diminish that both for the producer and consumer. As another said, they also introduce the chance of fraud by intention or mistake.
That said, I think overall fakes provide excellent advertising for the real thing and probably increase profits. Anything widely faked implies the real thing must be valuable.
Fakes are only a problem if they're falsely advertised. If something says "Rolex" but it is not, then that's a major problem. This is why trademark laws exist. But if something looks like a Rolex but says something other than "Rolex" on it, that's fine.
Samsung has never done anything remotely like appropriating Apple's trademarks, so it's all rather silly. There's huge difference between a knock-off and an outright fake.
It can hurt you if you were conned into paying a Rolex-level price, and/or thought you were buying an actual Rolex. And maybe you weren't, but I imagine plenty of people are.
I think this (intentionally or not) points out some of why people want Apple to beat Samsung. Not just win, but beat Samsung. It ties in precisely with what the grandparent is saying.
People want to choose sides and, for whatever god-forsaken reason, there are still people who haven't used it since 2.0 convinced that Android is massively inferior, and thus they see this as Apple beating a knock-off.
But it's not, and anyone whose seen Samsung's sales figures knows that.
And I think another issue here is that it isn't the case that Samsung attempts to con people into thinking they're buying an Apple device. Even if you get up in arms saying that Samsung/Android copied certain features from Apple, it would an entirely separate can of worms if people regularly bought Samsung devices, thinking they were buying an Apple one.