There were people on a particular linux forum, not everyone who use's linux. xP
NSA isn't spying on everyone, the argument is the 9/10 people were random people, so they could be spying on a lot of unconnected/innocent people. [
1][
2]However, the vast majority were strongly connected to the individuals they were investigating, just they weren't in on their plans. "Other valuable material reportedly revealed by the messages include information about "a secret overseas nuclear project, double-dealing by an ostensible ally, a military calamity that befell an unfriendly power, and the identities of aggressive intruders into U.S. computer networks,"
The second argument is that they have the technology to potentially spy on everyone.
But two officers and a van have always had that ability, so it's not really that big of a deal imo. They don't have the manpower even if they tried, so I'm not too concerned.
In any case, usually when they do an investigation 9/10 people they investigate are innocent. Like, take a murder; they usually first investigate the husband/wife, the friends, coworkers, neighbors, the known associates, people who could potentially have motives, and so on. Obviously the majority of these people end up being innocent; but the only way to prove that is to do preliminary searches about them to figure out information to exclude them. They need probable cause to initiate that search, but just being a close associate to this person is usually enough. There's differing levels of justifiable privacy invasion to do an investigation, however, this is more or less how they've done things for like, forever.