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.
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.