Granada was also the place were fascists killed Lorca

This is most likely a reference to both the Andalusian city in Southern Spain, one of the worst effected areas during the Francoist White Terror, and the Caribbean country of Grenada (due to the similar name and provocation) which had been invaded by the US several months prior to the release of this song. The Oh Mi Corazon helps show this as it expresses dismay over the recent and historic events that unfolded in these two areas.

Waters was especially moved by a letter he received from the Palestinian-perspective news source Electronic Intifada. The letter cites a parody written in 2005 for Palestinian school children -

We don’t need no occupation
We don’t need no racist wall
No more siege and no more curfews
Soldiers! Leave us kids alone
Hey! Soldiers! Leave us kids alone!
All in all, you’re just another brick in the wall
All in all, we’ve just made another break in the wall

Waters went on to pressure other artists against performing in Israel. In 2011 Waters wrote about his experience in The Guardian, and in 2017 he expressed his views in an op-ed for The New York Times.

This does not explain the lyric

Does not explain the lyric’s meaning.

This whole song is, as previously mentioned, a criticism on how society and school prime the way we think by giving us ideas and creating a rather dogmatic environment which utilizes “thought control”. It may also be emphasizing the Marxist idea (I’m generalizing) that our society is divided into to categories exploited(students) and exploiters(teachers) and that these are in themselves divided into subcategories being: the knowingly exploited, the knowingly exploiting, and vice versa. Teachers are a very big influence as to how people think, and a majority of the world has made this observation, people are yearly becoming more stupid, ignorant, and conservative. This is also an influence on the whole song since the malusage of grammar contradicts the general truth of the thing that is being said, creating a type of aphorism. This however is only one approach.

The other being that the song is trying to emphasize that we do need everything the lyrics are apparently against, and also that without teachers to prime our ideas we would not have the same ideologies that we have.

It might be a reference to the book “1984” by George Orwell, the dystopian environment where “thought police” were looking for people who committed “thought crime” and this forced them to “build a wall” for their emotions and thoughts from the outside world.

That’s interesting, but it doesn’t help explain what the lyric means.

Henry Rollins did not get his professional start in Olympia. As stated below, before he changed his last name to “Rollins”, he went by his birth name of Henry Garfield and he recorded with S.O.A. in DC and gigged around in the area. This is documented on the Dischord release “1981: The Year In 7 Inches”. Rollins first gig with Black Flag was as Henry Rollins and it took place in Costa Mesa, CA. All of this is extremely well documented. There is no documentation to suggest that Olympia WA was a place of any kind of importance or significance to Rollins early in his career or later.

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All of this is spot on, save for the part about Henry Rollins getting his professional start in Olympia. Rollins recorded music in DC (back when he was still going by his birth name of “Henry Garfield”) in a band called S.O.A. which stood for “State of Alert”. He and Ian MacKaye were friends, and this was long before Rollins had ever been to the West Coast. Rollins' first gig with Black Flag was in Costa Mesa, CA. There is no significant connection between Rollins and Olympia.