I've never understood patriotism, what is that make you identify with a piece of the earth's surface which has due to haphazard historical events fallen under a particular governance.
Also, in a democracy, the current state is based on the decisions of the local ancestors. I identify with those decisions more in some places than others.
What exactly in Snowdens leaks would increase the chance of terrorist attacks on the US ?
Wanting the country you live in to be safer and stronger is certainly not basic self-interest: that would be wanting oneself to be safer and stronger, without regard for anyone else. It is certainly nationalism, if not quite patriotism.
The parent responded to "made the US safer" and "made the US weaker". The point is that there is a bigger picture than the question of the USA's safety or strength: the effect that the Snowden's revelations have had on all humans when taken together.
> Even the least patriotic people generally prefer not to be murdered by terrorists
You seem to be saying that the desire not to be killed by terrorists is a good reason for the citizens of one nation to be want it to be safer and stronger than another nation. Perhaps the desire not to be murdered by terrorists is a good reason for all nations to be, together, safer and stronger.
I'd also like to add that wanting the country you live in to be safer and stronger against inside threats is also patriotism and self-interest. In my experience people also generally prefer to be secure in their person, property and privacy against those that would exploit them.
Of course how we each value and prioritise these things will skew our definition of patriotism and our perception of actors like Snowden.