Should we concur with Mr Hewett's final conclusion - and I see no reason not to do so - we would thereby accept that even those fundamentalists who oppose its practice must regard Western music as a kind of language that communicates things that they want to preclude from communication, otherwise they would not feel the need to ban it.
I read the article you're talking about, and my initial reaction was not that they had a certain respect for the power of music, but that they see in it just a Western influence that they wish to squash. I had a hard time reconciling what I know about Western classical music and what they
say they think its possible influences are. I don't believe that they
really feel that it seriously undermines or threatens their own culture; I think it's mindless extremism and nothing more.
It would make more sense if it was nationalist music they had a problem with. But the music of Mozart or Beethoven, who are mentioned in the article, is not. Beethoven's 9th - if you wish to take a message from it - conveys brotherhood, equality, etc., a positive message for people of any faith. Everyone should be able to listen to if they want to, but the Iranian government either won't or can't accept its universal and autonomous nature simply because of where it comes from.
It does make an interesting parallel with how, for example, rap is viewed here by many who believe it encourages violence and sexism and glamourises gun culture. It's only ever non-musicians and non-rap listeners who make such claims.
To the original question, I think it could be seen not so much as a
language, but a form of communication (though some might consider communication in any form to be a type of "language", I suppose) that can bring people together, but only
within certain cultures. As donjuan said, we in the west might not be particularly moved to feel anything by listening to African tribal music. But a performance of Beethoven's 9th under certain circumstances almost certainly will, evn by those who don't listen to classical music at all. If anyone has seen
V for Vendetta in the cinema, its use of Tchaikovsky's 1812 Overture is a good example. (It's a really good film, incidentally. I'd recommend it.

)
Jas