Dijkstra was a great scholar, but often very extremist in his thinking; probably he was well aware of his extremism and even use it as a tool to over correct some issues.

For instance, he was very right about the goto abuse but the idea of removing a powerful tool from your belt just because can be abused is a bit too much. Here I suspect is happening the same, he was concerned about people learning a lot of languages but not mastering a single one, still that doesn't negate the advantages of master one language and learning more.