Earlier quoted context omitted.
Few spies self-identify as someone who hurts innocent people. They think of themselves as supporting their family while helping their government or something. Don't focus on what nouns different parts of the spying apparatus choose to label themselves with, or what other functions they serve. Instead, consider their effects in the context of being a spying apparatus.
But how is it spying if you use the service voluntarily, they tell you exactly that they collect and often (always?) let you opt out of the collection. That's a really diluted standard for "spying".
The spies that saying warns of were not crawling around in vents with night vision goggles, they were your friends, neighbors, and coworkers who would relay semi-public information to a processing center that used the info towards harmful ends.
I see this situation as a direct analogue. We communicate naturally with a supposedly disinterested or trustworthy party, who then collects that information and distributes it to others, without our best interests in mind.