No argument there. But I'd point out that the Clash wasn't so much leftist as anti-authoritarian. Their lyrics also included the lines
"If you find an Afghan rebel that the Moscow bullets missed
Ask him what he thinks of voting communist:
Ask the Dalai Lama in the hills of Tibet
How many monks did the Chinese get?"
Lester travelled with the Clash to write an extended article for NME I believe.
He tried to talk politics (Marxism/socialism) with the Clash and their fans but neither group seemed interested (and Lester even says that the fans are not attracted to the band because of any political content in the songs).
Good example, good song too ("Washington Bullets"). I read in "The Last Gang in Town" that Strummer wanted to provide a little balance to all the criticism of the US on "Sandanista!" so he came up with those lyrics. Their infatuation with the Sandys was based more on a liking for the fact that they toppled a horrible dictatorship than on love for Ortega, though I wonder if they ever regretted being such obvious supporters (FSLN bandanas and the like). Again, "The Last Gang in Town" (great Clash bio) points out that naming their album Sandanista and all the pro-FSLN stuff was more symbolic than explicit approval of the Sandys per se. Still, as PJ O'Rourke said about the Sandys and the fact that they did get rid of the awful Somoza, "It's one thing to burn down the shithouse and another to install plumbing." I also read on FR that Strummer made some comments saying that Islamic fundamentalism was a threat to freedom or something of the like.