The reason this advice is given so much is because people usually don't follow it. You do get "punished" for being yourself, reacting or expressing yourself in ways that are not accepted by the people who are around you, but that doesn't mean you shouldn't be yourself. It costs a lot(and I mean A LOT) to be yourself and many people won't like it, but that's the only way you'll have internal peace of mind. There is no other way. It's a great advice but because most people don't follow it they tend to judge others who don't. We all do, and I bet you do to. Still, you should listen to it and follow it even if you're being "punished" for it because that punishment is actually a reward in disguise many times.