I wonder if Google would like to comment on why Android TV uploads so much data even when all the syncing options are turned off
Why might that be? Could it be that you're the product, and the single purpose of Android TV is to gobble up as much data as can be gathered about your viewing habits as possible, in order to pimp you and other Android TV users to advertisers, or enhance the targeting of Google paid services? Even if you've got all the privacy options enabled, do you really trust Google?
And it isn't just simple channel/streaming choices that help them, it is the full panoply of TV watching behaviours. When the set is on, how long for, how much time spent browsing for content, choice of content, viewing abandonment data (where a programme is not watched to completion), series content viewing metrics (eg, do you watch all of a series, dip in and out, binge-watch, watch the first few and give up, do you follow on season-on-season), is the set used as a dumb client for other sources, is there a balance between gaming and passive consumption, what the balance between free to view and paid content, what the balance between broadcast and catchup, if using a PVR, are you ad-skipping, etc. And if they can get access to cameras and mics, well, its open season on you.