It’s not the only factor, gravity also impacts time’s relativity. Funny enough as you trend towards the speed of light your mass/gravitational pull approaches infinity. It’s understood that when observers disagree about an event they are moving at different speeds, or are in frames of reference with varying gravity. My physics is rusty, but that’s roughly it. The discovery of relativity is not necessary to know that correlation does not necessarily imply causation. Ice cream sales increase in the summer when it’s hot (correlation), but clearly ice cream sales do not change the temperature of the globe (causation).

I guess I’ll have to listen to what that guy was saying to get why he had to being in relativity to explain that correlation is mot always causal