Of course they will only talk via lawyers! That's what they have to do to make sure that all communication is clear, documented, and not misinterpreted (by either party). Once the problem escalates to be a legal dispute, this is the only way communication can happen.
And as soon as this escalates to a lawsuit, the existence of the dispute will be public.
>If PEU can hold trademarks, why can't Fundación?
No one is saying that they/you can't hold trademarks. You just can't register ones that would be confusing to the public (which is the purpose of trademarks -- to avoid public confusion). And honestly, even the domain name postgr.es is confusing.
From the PostgreSQL EU website (as linked by you), these are their specific trademarks:
PGConf, PGDay, Postgres Conference, PostgreSQL Conference
These don't seem to be confusing about what the database itself is called, or how the project is managed. Trying to trademark "PostgreSQL" and "PostgreSQL Community" is way too confusing with respect to the primary project. You're basically trying to take over the global naming rights for the entire project. Whatever the relationship is between Postgres Core and PostgreSQL EU (and it is a bit opaque), that's not for you to judge and it has no bearing on what rights you feel Fundación has to the trademark "Postgres" or "PostgreSQL".
One reason why you're getting slammed so hard on this is that these have been hard learned lessons in the FOSS community over the past few decades. Trademarks are one of the few FOSS-compatible ways to protect projects, names, and publicity -- especially against commercial entities that may not have the best intentions. They must be defended in order to protect these projects.
And I'm sorry, but the global stability of the Postgres project is far more important than whatever good intentions you had.