Yes, and so is Amazon. I have six Echo devices in my house. I've taken to muting all the mic's on them when I don't want to listen to music.
Contemplating getting rid of all of them, the problem for me is they've become so useful. My favorite task is to go through my kitchen cabinets and create my grocery list using a skill I wrote. I have it connected to my daily calendar so I know where I need to be ahead of time, I can make calls with it (including yelling "Alexa, call 9-11" and then tell it to open the garage door in case I fall so emergency personnel can get in my house.)
That is the problem with technology like this though, isn't it? It's so easy to weave into our daily lives and increase convenience that we become spied upon and listened to.
I've had a similar experience as you where ads pop-up in my browser that are related to discussions I've had in my home and that's why I mute the mic's now.
There is an article on the interwebs about how to delete all the files that Amazon and Google have from listening to you if you care to find it, and one about how to disable that feature on Alexa. I'd post it, I'm on my way out the door to work ...
“There is an article on the interwebs about how to delete all the files that Amazon and Google have from listening to you if you care to find “
You can delete them; that is YOUR ACCESS to them. They don’t show up for you any more. Google keeps them.

You could just ask Alexa to post it for you.