The software freedom conservancy has tendered its response:
http://sfconservancy.org/news/2018/sep/26/GPLv2-irrevocabili...
http://copyleft.org/guide/comprehensive-gpl-guidech8.html#x1...

""
"The GPLv2 have several provisions that, when taken together, can be construed as an irrevocable license from each contributor. "
""

It cites:

" That license granted to downstream is irrevocable, again provided that the downstream user complies with the license terms: "[P]arties who have received copies, or rights, from you under this License will not have their licenses terminated so long as such parties remain in full compliance" (GPLv2§4). "

However this is disingenuous

The full text of section 4 is as follows:

""
4. You may not copy, modify, sublicense, or distribute the Program
except as expressly provided under this License. Any attempt
otherwise to copy, modify, sublicense or distribute the Program is
void, and will automatically terminate your rights under this License.
However, parties who have received copies, or rights, from you under
this License will not have their licenses terminated so long as such
parties remain in full compliance.
""

The "You" in section 4 is speaking of the licensee regarding sub-licensees, it is not speaking to the licensor/copyright-holder.

IE: if the licensee loses his license, through operation of the automatic-revocation provisions, the sub-licensees do not also lose their licenses.

IE: The language is disclaiming a chain topography for license distribution, and instead substituting a hub-and-spoke topography (all licenses originating from the copyright holder, not the previous-in-line)

GPLv3 added a no-rescission clause for a reason: the reason being to attempt to create an estoppel defense for the licensees against the licensor. You will notice that Eben Moglen never speaks on these issues. (He preumably is aware of the weaknesses vis a vis the US copyright regime.)

Section 6 further clarifies the hub-and-spoke model:
""
6. Each time you redistribute the Program (or any work based on the
Program), the recipient automatically receives a license from the
original licensor to copy, distribute or modify the Program subject to
these terms and conditions. You may not impose any further
restrictions on the recipients' exercise of the rights granted herein.
You are not responsible for enforcing compliance by third parties to
this License.
""

The memorandum posted then goes on to a discussion of estoppel, detrimental reliance, etc; noting that users may have relied on the software and their licenses may be estopped from being revoked from said users since doing so might cause them unanticipated loss. This is speaking of already published, existent, versions of the program used by end users.

The memorandum seems to ignore what happens to "upstream" once said project receives a revocation notice. Thought it may be possible that users of a published piece of software may have defenses to license revocation, the same is not true regarding the rescinded property vis-a-vis future prospective versions of the software nor of future prospective licensees of said software.

That is: once the grant to use the code in question is rescinded, future versions of the software may not use that code. Current users of the software may be-able to raise an estoppel / detrimental reliance defense regarding the current published software, however the programmers working on the next version of said software cannot continue to use the property in future versions of the software (such would be a copyright violation once the gratuitous license is rescinded by the grantor).

Additionally, prospective-licensees, once the grant was rescinded and such was published, would have no same-such estoppel defense (not being user-licensees at the time of revocation).

(Ignoring this eventuality in the published memorandum, is, of-course, by design.)
(Now, to note: the free-software movement is focused on the freedom of the user, not the progenitors of the software, so one could certainly say that ignoring some developer-focused analysis is consistent with their prerogative...)

--------------------
--------------------

Gnu GPL version 2, section 0:
"Each licensee is addressed as "you". "

The "you" is not referring to the licensor (copyright owner). It is referring to the licensees and then future sub-licensees/additional-licensees receiving the work from said previous licensee.

It is independently clear from the context of the clauses if you read them in full.

...and then section 0 comes around and makes it _explicit_ that "you" refers to the licensee. (if you had any doubt)

Additionally, you should know that the copyright owner is not bound by the gratuitous license he proffers to potential licensees regarding his property. The licensees are bound to his terms: he is the owner. They take at his benefaction.

<blockquote>
GNU GENERAL PUBLIC LICENSE
TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION

0. This License applies to any program or other work which contains

a notice placed by the copyright holder saying it may be distributed
under the terms of this General Public License. The "Program", below,
refers to any such program or work, and a "work based on the Program"
means either the Program or any derivative work under copyright law:
that is to say, a work containing the Program or a portion of it,
either verbatim or with modifications and/or translated into another
language. (Hereinafter, translation is included without limitation in
the term "modification".) Each licensee is addressed as "you".
</blockquote>