The default matrix.org servers are federated.
In terms of what the default Element install presents to the user upon launch in its GUI, I think it does offer the 'official' matrix.org servers as a place to create an account and sign in, start browsing 'rooms'.
what is the actual state of matrix e2ee today? (or is that question silly because it depends what the individual matrix clients chooses to implement).
I'm extremely excited about having a federated e2ee messenger, however as a "Lawful-Intercept" realist, I don't have a lot of hope that it will not get forced to comply with current EU regulation proposals, that prevents Matrix from fulfilling its promise as fully e2ee. (e.g. the future that we're heading to in the EU is the same as 5/9-eye countries: there will be a "legal" way of encryption and another one that is illegal, all depending if access can be given to 3rd parties / LE...)
[1] (Sad) state of E2EE in Matrix clients (from 2018): https://www.reddit.com/r/privacy/comments/9avyen/sad_state_o...
Why do you say there will be, as if the future is predetermined? Perhaps we should re-evaluate that and help prevent it from happening instead of complacently stating something as if it is a foregone conclusion?
Your words matter here. The way you are using them is helping materialize the future you do not want.
With Matrix you have the choice to use whatever server or client you like, which makes it difficult to censor.
But given E2E and the Sealed Sender[0] functionality, they could only suppress messages based on the recipient's user ID, not based upon message content or the sender's ID. This all or nothing approach is a rather ineffective method of censoring – it basically just amounts to banning a user account. I wouldn't even call it censoring in the first place as that term, at least to me, refers to a more selective and refined approach.
> (And they do, for example you can "delete" your messages that are stored on other clients.)
This has nothing to do with censoring and nothing to do with Signal controlling "both server and clients". The Signal developers simply extended the protocol to include "delete" requests for previously sent messages. The client app still needs to implement the actual deletion, though. You could easily compile the Signal app yourself with that functionality removed and then nothing would get deleted from your message history anymore.
I mean, sure, 99% of users are not going to do this. But this is no different in the case of Matrix, where most people just download the default apps like Element from the app store.
So I don't even understand what your statement
> they control […] clients
is supposed to mean. Yes, they write the source code. So? Someone has to produce and maintain the source code and whoever does it will obviously be in a position of power. Producers are always going to decide what they produce. Consumers don't get a say in this – unless they become producers themselves (and in case of open-source software) adapt the product to their needs. Again, this is nothing new and is the case with Matrix, too.
To put it in terms of your logic: it that were case, it means Signal is not secure.
It seems this always requires the /sarcasm tag. =)