Dijkstra thought of computer science as a subdomain of mathematics, and thought that hands-on experimentation with actual computers would mostly lead students astray. A program should all be worked out and proven correct before (optionally) feeding it to a computer, and testing and even more so debugging were abhorrent practices.
BASIC, on the other hand, is more aligned with what Seymour Papert later came to call "Constructionism": the student learns by experimentation.
Ironically, I grew up with limited access to computers, so I wrote many programs on paper first, including a FORTH implementation in assembly language I wrote over summer break with a typewriter, waiting for school to start again so I could actually test it hands on.
BASIC, on the other hand, is more aligned with what Seymour Papert later came to call "Constructionism": the student learns by experimentation.