Does Metamask not really know what tokens I own?

This clip claims that Metamask does not really known which tokens I own:

https://youtube.com/clip/UgkxSTDXnku5O8ldTXPz179wparSMPSMeYlh

It also suggests that I don't really 'control' the tokens but that they are in control of a third party smart contract which basically has a liability to me.

Crypto appeals to me since because of full control and ownership, but this suggests otherwise.

So, is this true and how can it be fixed?