The problem is, your smart TV could be spying you too, if it's capable of voice commands or videoconference. If you discuss sex toys near it, at least some related keywords could make their way to targeted advertising.
My wife and I routinely use ad blockers, private browser windows, browser profiles, and try to use as little ad-supported products as possible. This doesn't stop targeted advertising, I guess because most devices we use connect through the same IP. A couple of days after she starts looking up a city we want to travel to, I'll start receiving ads from airline companies or travel agencies, and even tours/cruises to said city/region. Fighting tracking and spyware is nearly a lost cause unless you become a digital Amish.
Smart TVs in general use IP address to try target devices across households, which is against the privacy policies of a lot of ad tech providers because IPs are not redactable/resettable by an end-user.
The best way for small ad tech providers to compete with "big tech" has been to cross lines that the bigger companies won't cross, this is an example for why there are a lot of profitable ad tech companies in the connected TV / video ads space.
Even if you use a VPN, the TV itself likely has a unique ID for ads, so someone just needs to see one request with both the true IP and the unique device ID and then remember that for the future. It's all very shady. TVs are very far behind the level of user control that phones and browsers provide because there's less scrutiny and its more fragmented across manufacturers (all of which want to get in on ad tech).
You can usually find some opt-out of the identifiers if you dig deep enough into the menus, because multiple laws and regulations require them.
The first thing I did when helping my parents set up their new LG OLED TV's at xmas was to disable all the ads and tracking. It's exhausting how much pressure they put on you to opt-in, and how many layers there are, constantly implying the TV will be nonfunctional without it.
But sure enough, it works just fine with no ads, no "free tv channels", and no voice functionality.
Have you ever checked back to see if updates had re-enabled some of those or introduced new ones? You'd hope they'd let you know if they started getting ads all the time, but the tracking stuff is much less obvious.
LG will send out updates that require you to accept new license agreements when you turn the tv on next. It’s very obvious about what they are tracking but very obnoxious in pointing it out. The parents that OP refers to probably just clicks accept all and moves on.
We have an LG tv and one of my family members hit accept all after an update and now my remote listens to us. To fix this properly I would need to factory reset which loses all of our streaming settings. I actually don’t because I have a separate ISP only for our TVs so there’s a bit of separation between our streaming use and phone activity
