I believe that patriotism has slowly morphed into nationalism for many people. The line between the two has become so blurred that I don't think those people are even aware that there is a difference.
Patriotism has gone from a sort of unconditional love and devotion to one's nation to a "if you're not with us, you're against us" mentality. It's okay to enjoy being a part of something, but that should never turn into an "us vs them" way of looking at things.
It is difficult for some people to understand how someone can love their country, yet at the same time, respect and even appreciate the differences of other countries. Or, how that same someone could ever think to criticize their own country when they feel it's appropriate.
I don't know how many times I've heard the phase "If you don't like it here, then get out!". People often confuse someone's discontent for the way things are done as a sign of not caring, and these people are often labeled as being "unpatriotic" and rejected.
Also, speaking praise or approval for another country's actions is almost considered sacrilege these days. Doing so might get you the typical, "If you like it so much, why don't you move there?". I feel that ultimatums like those are people's way of avoiding having to face a problem because they don't want to rock the boat. They'd rather just accept things as they are while taking pride in something that they don't even fully understand.
Personally, I think patriotism has become a spark just waiting to ignite discrimination. There has always been discrimination between nations, but that discrimination can just as easily include individuals living on the same piece of land, and pit them against each other in needless conflict.
Human beings will forever find any excuse to hold on to anything that keeps them isolated and detached. And I'm not talking about globalization. I'm talking about our perpetual and willful ignorance of the fact that we are all one - regardless of national, political or religious stance. Every time we overcome one of these discrepancies, we invent a new one.