I would argue that it is the other way around; given the forced choice of "only one" the broadest support exists for PGP.
I don't see anyone talking about "only one". Why are you worried?
Well, that's not quite precise. The document under discussion talks about securing communication to and from RIPE NCC registration services mailboxes, e.g. hostmaster@ripe.net etc. -- typically functions where humans at the RIPE NCC are involved in resolving the matter (yes?). Therefore, I perceive this as explicitly excluding auto-dbm@ripe.net. Add to that that Shane Kerr has explicitly said in this discussion that none of the current PGP support will be removed. However, the document under discussion appears to offer X.509 as the only method for securing communication with RS mailboxes, the alternative is continue as today, where this communication is going unsigned and in the clear in both directions. Regards, - Håvard