So your TV just connects to random wifi networks? That sounds a bit insane.
That example isn't a random wifi network, it's the Xfinity network.
But also, you think tv manufacturers are sane? They have proven that they don't deserve the benefit of the doubt, in my opinion.
It doesn't sound insane, actually. Keeping in mind, Windows XP did exactly that for a while until everyone realized, "hey, that's a security issue". I would swear MacOS too, but I wouldn't bet money on it.