BASIC is explicitly a beginner's language. It may not be the best design for advanced programming, but as an instructional tool for someone who doesn't even know what a program is, it's almost second to none. The lessons it teaches are profound: that programs are ordered sequences of instructions that computers can follow, that control flow can involve branching, loops, and conditionals and what those are, and the rudiments of breaking out a program into subroutines. This is a real mindblow for people who've never actually programmed before -- it means they can make the machine do what they want, even very sophisticated (from their perspective) things. It's only when you've seen better -- Algol, Pascal, Lisp -- that BASIC seems miserably wrong in comparison.

As for Dijkstra -- arrogance in computer science is measured in nanodijkstras.