Leonardo DiCaprio is literally the most in-demand actor in Hollywood. People say that all scripts pass through him on their way to anybody else.

I'm just saying that a hyperproductive class A talent only working once with another class A talent is a little odd.

Also notice that the first thing I said was maybe they are enemies. Maybe Leo slept with Spielberg's daughters. Maybe he insulted Spielberg's directing. It could be literally anything is the point-- including something as jarring as antisemitism. It's probably not that, but it could be anything. So let's not pretend that every other actor that has worked with Spielberg once is on the same level as Leonardo DiCaprio. That's just silly.