Is Alexa spying on me?

I bought a house, and there are "smart" things in that house.
A smart (Ecobee) thermostat
A smart microwave
A couple blink cameras
A smart (z-wave) door lock
A smart (ring) doorbell
A smart tv
An Echo dot

My younger brother is a retired FBI agent. He came to the new house for Thanksgiving and the 1st thing he did was to unplug the echo dot. He said it is eavesdropping on the house, the signal is going somewhere else, leaving the house, and can use some of the other smart appliances to listen also.

Paranoia?

Or perhaps there is something to it?

Google has already admitted to listening in, google staff have heard recordings of people having arguments, having sex, making drug deals and personal conversations. They say its to improve the technology and voice recognition... of course it is...

SH420