> Lots of sites that handle user-generated content have, in their terms, an irrevocable license grant to allow them to reproduce and distribute your submitted content.
Those are not gratuitous licenses granted by the rights holder, they are contract licenses in which the license are part of the exchange for services the site operator is providing for user.
> Try revoking one of those and suing a site for infringement on grounds that it's impossible to grant an irrevocable license,
I never said it's not possible to grant an irrevocable license. I said gratuitous licenses are revocable at will as a matter of law. I expressly noted that free software licenses are not, in all circumstances, a gratuitous.
Those are not gratuitous licenses granted by the rights holder, they are contract licenses in which the license are part of the exchange for services the site operator is providing for user.
> Try revoking one of those and suing a site for infringement on grounds that it's impossible to grant an irrevocable license,
I never said it's not possible to grant an irrevocable license. I said gratuitous licenses are revocable at will as a matter of law. I expressly noted that free software licenses are not, in all circumstances, a gratuitous.