Is it ALWAYS necessary to understand words of song?

...throughout my devotion to music of different kinds and songs, I've realized that songs of Paul McCartney, Queen, Led Zeppelin and other Brittish rock bands motivated me to learn English.
I am learning French now -- guess for what reason?
-- Very simple:
I adore french femail chansons such as Mireille Mathieu, Edit Piaf, Juliette Greco, Patricia Kaas.
I also like male singers Joe Dassin and Charle Aznavur.

The fact is that on the first place I did not understand neither English or French.

There are other performers that sing other than in English or French that I like and do not understand what they're singing such as Gipsy Kings(Spain), Cesaria Evora(Sinegal), Los Joven'os Flamencos(Spain), Nina Hagen(Germany) etc... but these performers did not yet motivated me to learn their language since they're almost "one of a kind"

It is almost impossible to aquire non-english/non-latin CDs or records on the territory of US. The're all either in Canada, Europe or even Asia!

For live performances,for example, Nina Hagen(Germany) didn't sing any of her songs in German in NY. It's very rare or almost never in US that popular rock/pop singers from european countries other than UK will perform since they probably have to sing in English.
The only exception I know is Cesaria Evora that sings in Portugese. She performed in Carnegie Hall and Beacon Theatre in NY.

I was on live performance of Mireille Mathieu in Kiev, Ukraine where I can bet that most of the ticket holders did not understand French. In fact, there is no need on the first place since her voice and artistic scene play makes people understand her without knowing her language. She crossed over the whole World with her live concerts except US.

Please share any thoughs and/or arguments. Is there anyone who listens songs without understanding words?
If yes, tell who do you like, what language he/she sings and what country she's from?

Hopefuly in few months I'll make a post in French!!
I hear a lot of rap music (mostly from cars as they're parking or passing by) and all the words sound the same -- I think they're an English derivitive of some sort, but I'm afraid I don't understand any of it. From their general tone they seem very angry -- my guess is that most rappers aren't gettin' any. :)

I wish they could get some so they would shut up or sing a different tune.
I have some german and french David Bowie imports (Records). They have the same songs for the most part as the US releases, however David sings some of the songs in german (and french). Fun to listen to. I have a few more records that are similar by other artists.

Anyone who listens to classical or opera would probably find english strange (unless its the native language of the composer).

How about Cocteau twins? Its English but you can't decipher many of the words in their songs. I don't care because it still sounds great. I look at the voice as another instrument.
Hey, I had a neighbor that went around singing "Felix Doughboy the Hero" to the tune of "Billy Don't Be a Hero" (a bubblegum hit in the US back around 1970 or so, iirc). Sometimes, its even better when you don't know the words - to this day when I hear that song, I remember Faye, cleaning her house, cigarette (remember those?) dangling from her lips, singing away! And I think "Felix Doughboy the Hero......"

Slightly off topic, but I must admit I don't really listen to the words in music in order to get what is being said. To me music is about emotion and the poetry in the words is all that gets through to me when i am grooving to music. To focus on what is being said literally, for me would be a distraction from the music.
Not even the F.B.I. could decipher the words of Louie Louie.