> The above observations regarding moral rights imply that putting code under an ISC or two-clause BSD license essentially makes the code as free as it can possibly get.
Emphasis on: or two-clause BSD license.
That said, the ultimate recommendation on the page is ISC, but only because:
> The ISC copyright is functionally equivalent to a two-term BSD copyright with language removed that is made unnecessary by the Berne convention.
The OpenBSD project uses the "and" wording, whereas the license text on the OSI website uses the "and/or" wording.
Given all this, it seems to me that recommending the 2-clause BSD is the most straightforward option, because its only (and innocuous) issue is that it contains some no-longer-necessary language after the Berne convention agreements.
[1] From Wikipedia: When initially released, the license did not include the term "and/or", which was changed from "and" by ISC in 2007. Paul Vixie stated on the BIND mailing list that the ISC license started using the term "and/or" to avoid controversy similar to the events surrounding the University of Washington's refusal to allow distribution of the Pine email software.
ISC isn't perfect but it's a far better license than BSD.