I disagree strongly with your view, and in my view the bank were absolutely in the wrong.
If his account hadn’t been closed for commercial reasons due to his political beliefs, then the BBC wouldn’t have had to issue a public apology.
I think what Farage is doing in this instance is a good thing. The banks are in a very privileged position, and should not discriminate against customers just because of what the bank believes the widely held beliefs of the day should be.