This depends on the meaning of "sniff them." If you mean by this, that the attacker needs some way to get active equipment into your data stream, then yes. But a sufficiently advanced attacker can of course always get his equipment into your data stream. For example by using directional antennas to spoof a wifi hotspot, or digging a hole and splicing it directly into the optical fiber.
Yeah, I don't doubt the government could perform active attacks on more targeted individuals if they wanted to, but this mass collection of internet traffic that's supposedly happening is almost certainly passive.
