By flattening and rotating the polarized lens 90 degrees, light emitted by LCD/LED screens is blocked, making it look like the TV or computer in front of you is off.
That's true, but the Galaxy S series has used AMOLED since it was introduced in 2010.[0] Looking in more detail my guess is it's not majority market share but it's definitely significant.
Granted, my 2011 Nokia N9 also had an OLED screen. But they became unfashionable for several years due to (then) poor color rendering (although their contrast, naturally, was and is top notch). Currently they've been making a comeback.
Perhaps by LED they're referring to LED-backlit LCD displays. There's pretty much full coverage of the visible spectrum across different LED types, so the only way to block them is with completely opaque lenses.
That isn't how polarization works. It isn't about the spectrum it is about how it travels or is reflected in a more uniform way (normally horizontal. So if you block out horizontal light you get rid of glare or in the case of panels you stop seeing the screen.
Right, well we aren't talking about polarization since LEDs don't emit polarized light, so you'd need notch filters to block the wavelengths LEDs emit, but the notch required to block all LEDs would be entire visible spectrum.
By flattening and rotating the polarized lens 90 degrees, light emitted by LCD/LED screens is blocked, making it look like the TV or computer in front of you is off.
These won't work on phones nor Billboards.