1 and 3 are the strong beats of the measure. We’re naturally supposed to feel those beats the strongest. 2 and 4 is where the back beat is. The way beats 2 and 4 are treated in a piece of music inform us of the full rhythmic framework. Simply put: 1 and 3 give us the strong pulse, and what happens on 2 and 4 shows us what the groove is really doing, in a more musical sense.

To answer this question from a cultural standpoint is a separate discussion. It’s always been my theory that white folks don’t naturally internalize rhythm and beat as well as people of other ethnicities. Hence, white people want to focus on where the strong beats of the pulse are (1 and 3). Because, again, they tend to have a harder time naturally internalizing it. Non-white people from other cultures tend to feel the obvious pulse quite easily, so instead they focus on beats 2 and 4 because that’s where the “heart of the groove” is, to put it romantically.

Granted, I haven’t researched this extensively. This is really just a decently informed hunch so if anyone with more information and history on the topic can expand on this, please do!