I believe you register your device with Microsoft so Windows can automatically obtain and install drivers for them when they are plugged in.
What LG sent in for installation is not a simple .inf or .sys/.dll file. They sent in a whole bag of software which does all the nasty things, and Microsoft doesn't vet or care about the software installed as the "driver" of the hardware.
This is actually a feature of the .inf by design, an AddSoftware directive. It can even link to apps from the store instead of bundling them with the driver. This is designed to install settings panels like the ones for GPUs.
https://learn.microsoft.com/en-us/windows-hardware/drivers/i...
I guess that from Microsoft's perspective, the driver itself wasn't suspicious, but it installs a questionable sidecar app they would have never vetted anyway.