My LG has a Firestick on it. Updates and WiFi/ethernet are disabled. The endless nagging updates prompted me to sever its network connections six or eight months ago. Now it is a useful display.
Same here, I had to buy a new TV for the bedroom recently when the old dumb TV finally up and died. I ended up with a TCL, and I just moved the same Roku stick to it I was using and I ignored all the Google TV stuff.
Thankfully, I found the setting where I can have the TV come on directly and quickly to HDMI port 1 for my Roku, just like how the old TV did, with no waiting for any Google stuff to load.
Then I realized I had not bought a new TV in the last six years, and the reason that the picture looked like people were photo-shopped into the scenes was because of that new Motion Clarity setting that everyone hates. It took me like a week to figure out why the picture looked so strange and how to turn that setting off so I could just watch TV without being distracted by the image.
It is not so new that brand new TV's should not be defaulting to it off. I guess when something misses, they just double down instead of getting rid of it.
I don't think it should be on by default, given it is processing the video. It is on by default even for the HDMI sources, which should default to clean source.
It might just default to on for showroom or something. I admit, when I first turn on the TV, I thought, "Wow, this new TV has a really clear picture!" Then when watching a show with it on, my brain kept noticing how odd things looked, until it was actually annoying and it was all I could think about.
Sounds like this may be what we used to call the Soap Opera Effect...
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This is the first thing I turn off on every new TV, for every HDMI Port, and every mode of use (e.g. SDR, HDR10, Dolby Vision, etc...)
I love the picture quality on my LG OLED TVs, but they are all blocked from Internet Access.
That was my point. As long as people have been complaining, you would think they would default it to off by now (or even remove the feature).
Ah, I think you added a double negative accidently, making it read that it should default to on.
No, I added it intentionally.
Meaning, that is isn't so new that they should not be defaulting it off now.
Meaning, they should be defaulting it to off if they had listened to the feedback. But they are not
I know some people think I am just a contrarian, but I'll say that I know a lot of people that like motion clarity settings when used on their lightest setting to reduce judder/chop/improve motion. Myself included.
I never used to like it as the soap opera effect was extreme in the early days, but in the past 5-10 years or so I think they have improved drastically (again, typically on their lightest setting). 
All that said, I would be fine if the default were OFF, too. I am perfectly capable of adjusting my own settings.
Or even on the lowest setting as you said. I have a LOT of friends who aren't into technology and I have "fixed" a number of TV's that had these symptoms on their brand new TV's
For sure. Even though I personally like a little light processing, when it is on full blast it looks really bad (in my opinion).
I always used to to turn it off too, since I despise the soap opera effect.
But recently I’ve tried keeping it on low to see if it helps a little with motion blur without being annoying. Surprisingly, it hasn’t bothered me at all so I’ve left it on for my two TVs.
Maybe I will try that, out of curiosity. I went right to off, and I didn't play with settings to see if it can be usable.
The full blown soap opera effect drives me crazy - so I am DEFINITELY not advocating for that / saying that looks better. 
(lest anyone think I have lost my mind entirely)
For sure, I hate it so much I also offer to turn it off when watching TV at friends’ or relatives’ houses.
I was skeptical about turning it onto low and TBH I can’t even remember what prompted me to try it, but I’ve been pleasantly surprised.
It's called Soap Opera Mode. My wife and I are very touchy about that setting. She especially. If anything looks off, she has be make sure that setting isn't on.
The worst is when we're staying somewhere where they use a STB and I have to ask maintenance for the actual tv remote to turn that crap off.