It's not just that they're smart, it's that the "smart" features actively interfere with normal operation, though it's bad enough that you can't find "dumb" versions. TVs for example: a few years ago I tried to replace my dying "dumb" TV and discovered that they basically don't sell TVs that aren't smart. I figured "eh, worst case I can just use it as a normal TV" only to discover that on some models no, I could not. I've come to despise Roku-integrated TVs: standalone Roku devices are great, but their TVs lock down basically every single adjustment you'd find on a normal TV other than brightness and volume, so too bad if you have to deal with glare I guess?
Finally wound up going with an AndroidTV, which at least lets me change inputs and adjust the picture as needed... but also the home screen is loaded with ads that you can't disable. At least it still lets me have it boot straight to a specific input instead of showing the home screen.