To me the email
   at [1]https://lists.cpunks.org/pipermail/cypherpunks/2021-April/087371.
   html indicates that messages are likely being disrupted somehow.
   To me, it does not really show whether that is happening at pglaf, an
   isp or government, or the behavior of the poster of the message.
   I have heard others (James) complain of spam bouncing on this list.  I
   have never received a spam bounce myself.  I thought Greg stated some
   months ago that there was no spam filter on the host.
   The message would be _far_ more credible if it contained an actual raw
   copy of the bounce email attached.  But it still looks incredibly
   credible.
   The correct solution here is cryptographic message delivery.  It is
   clear the people running this list are being harmed, that there is no
   easy way, already, to prove what actually happened around that spam
   bounce.

References

   1. https://lists.cpunks.org/pipermail/cypherpunks/2021-April/087371.html