You need to trust the software you're using. It's a lot more difficult to compromise a coin flip than it is to compromise a recently sold paper wallet website.
That's why i said the following:
Don't ever use websites to create a paper wallet (neither online nor offline).
Trust required towards the software is true. But i'd say you can pretty much trust an officially signed open source linux distribution and openssl (or electrum).
Because that's basically all you need (or even less when generating it with coinflips). And that's what i was talking about.
But i was curious regarding the coinflips from o_e_l_e_o, and why he chose to use them instead of the other possibilities (openssl / electrum / core) on an airgapped computer (which has to be used anyway).