Why “camarada” means friend?

Question

It is common in Mexico to use the word camarada as a way to call informally a friend. For example:

• Tengo un camarada que es piloto.
• Ayer fuimos a la fiesta un camarada y yo.

RAE defines camarada as:

camarada.

(De cámara, por dormir en un mismo aposento).

1. com. Persona que acompaña a otra y come y vive con ella.

2. com. Persona que anda en compañía con otras, tratándose con amistad y confianza.

3. com. En ciertos partidos políticos y sindicatos, correligionario o compañero.

4. f. Compañía o junta de camaradas.

5. f. ant. batería (‖ conjunto de piezas de artillería).

6. f. ant. batería (‖ fortificación para poner a cubierto piezas de artillería).

As you can see the meanings are different from the real use in Mexico.

1. When did the word become popular?
2. Are there any other countries that use that word with that meaning?

Answer 1

I would say camarada is mostly used when referring to someone that shares your own political party or political view, in general (Wikipedia has a good explanation as to how and when it became popular). It shouldn't have a bad connotation but unfortunately in Latin America is mostly used by the far left, the far right and the terrorists in between:

• The PSUV (Partido Socialista Unido de Venezuela) uses camarada all the time. Check Iris Varela's twitter (current Venezuelan minister)

• Colombian paramilitary groups and guerrillas use the term camarada to refer to their members.

I believe the meaning as synonym of friend is understood everywhere, but personally, I would avoid it.

Answer 2

For the second question, in Spain, though it's not very widely used, it is perfectly understood.