A) Not charging differently does not mean it is free (which was the original argument).
B) The "target" bank can still charge you independently of your bank.
E.g. (and I do this kind of transfer very very often so I am 100% sure it is so and I am also 100% sure this is legal): A transfer from Germany to Germany is free. A transfer from Germany to Greece is not as the Greek bank charges a fee.
All banks in Greece charge a fee. The fact that plenty of people do SEPA transfers for free means nothing for the other people (e.g. the whole population of Greece) that can not do SEPA transfers for free.
First of all, you are not allowed to have a German account if you are not a resident of Germany.
Besides that, this is not the point of the conversation. The original comment compared SEPA to Bitcoin, saying that SEPA is better since it is free. It is not. There is no law that mandates it to be free and it is de facto not free everywhere (it might be for your use case but not for everyone). It is many times a lot more expensive than Bitcoin. If I also elect to not transact with Greek bank accounts, I exclude 99.9% of the Greek economy since I have no influence on what kind of account my counterpart has.
Direktbanken (i.e. purely online Banks) are an exception but they come with their own set of asterisks and are not a blanket solution as you can't open an account from all European countries.
There is no such exception. Banks are free to do business with whomever they wish. Direktbanken are usually probably the hardest to open an account with if you are a resident abroad.
Deutsche Bank is well known for offering accounts to non-residents. Pretty much any Sparkasse will open an account for you if you walk in even without a German address.
The list of banks that don't offer accounts to non-residents is probably shorter than the other. Granted, these are mostly the ones with the best offers.
B) The "target" bank can still charge you independently of your bank.
E.g. (and I do this kind of transfer very very often so I am 100% sure it is so and I am also 100% sure this is legal): A transfer from Germany to Germany is free. A transfer from Germany to Greece is not as the Greek bank charges a fee.