because "learning the shit out of any one algorithm" is not a very well-defined goal and is at best, a locally optimal strategy. If the OP's goal is to become literate in a many topics, then learning those topics in broad strokes may be better than learning all the details up front.
There often can be a vast literature on any one given topic or algorithm. Are you suggesting the OP acquire researcher-level expertise in everything? Everybody, at some point while learning, makes the decision as to whether or not they understand enough for their own purposes, and then chooses to dive deeper or move on to something else.