Siri can understand what you say. I'm not saying the person was right, but is it really far fetched? IIRC gmail already targets ads based on your email content (ie conversations).
facebook was found to be doing the same thing. Voice is just some data, companies have teams of engineers working on efficiently extracting that datastream and using it to sell you ads.
Orwell never predicted we'd be paying for the always on microphones to be installed in our homes ourselves, and be happy about them.
It seems most folks don't even see or care about where it's leading us.
Personally? It's almost ostracising to express strong opinions on this sort of thing even to our tech peers.
If you've also worked on tech which provides or enables this sort of invasion, then its hard for us not to really care about how we're doing nothing to stop it or to understand why we're not more angry.
Trying to get a dialogue going on it just makes people think you're a step away from being the crazy person with the tinfoil hat...
I'm a little skeptical of that one.