Secret motives aren't really the right argument, I agree. Citing the seemingly-inevitable negative outcomes may be a better approach.
When someone argues for ubiquitous mass surveillance, ask them to explain exactly how the Stasi worked, how they came to power and what can be done to keep it from ever happening again. Point out that these questions have to be addressed before arming the state with surveillance tools that previous abusive regimes couldn't have dreamed of.
That's the biggest thing that frustrates me about NWO (as a concept) used as a rhetorical device in argument: it's not necessary.
You have world history littered with examples of mass surveillance platforms being used for oppression.
No explanation or justification of why that happens seems necessary! It's a stronger and supported argument to just say "Whatever the cause, when mass surveillance has been implemented historically, it is eventually used to errode civil liberties and increase population control."
When someone argues for ubiquitous mass surveillance, ask them to explain exactly how the Stasi worked, how they came to power and what can be done to keep it from ever happening again. Point out that these questions have to be addressed before arming the state with surveillance tools that previous abusive regimes couldn't have dreamed of.