Your washing machine could be sending 3.7 GB of data a day — LG washing machine owner disconnected his device from Wi-Fi after noticing excessive outgoing daily data traffic
Well to be fair to giant spying companies, it would be fairly easy to sift through data as it comes in and only keep relevant metrics in a statistics database and throw out the rest before the day is through.
For giants like LG, Samsung, etc... it would be a drop in the bucket.
It's likely been hacked by someone who guessed the default login details (when was the last time you changed the password on your washing machine), and is being used for malicious purposes such as DDoS attacks.
My LG washer needed a key printed on a label on the door to connect it to the network. However that isn't to say that once on the network that the network itself wasn't compromised and the washer found as an easy attack surface.