I have to agree that this advice is awful too, unfortunately.
As an engineer for an early-stage startup you daily work and value add - shipping things and invest into deep engineering work, would not be very well aligned with networking and relationship building that would be beneficial to start on your own.
Another interesting idea to consider - as a FAANG engineer you would be able to angel invest already (or fairly soon). That would be a productive (quite expensive though) way to meet more people interested in the same things as you do.
As an engineer for an early-stage startup you daily work and value add - shipping things and invest into deep engineering work, would not be very well aligned with networking and relationship building that would be beneficial to start on your own.
Another interesting idea to consider - as a FAANG engineer you would be able to angel invest already (or fairly soon). That would be a productive (quite expensive though) way to meet more people interested in the same things as you do.