None of that is relevant to you having a baseline to compare against in order to make your determination that no advantage is gained.Because what I see 99.9% of the time are pitchers that are trying to pitch within the rules but have some sort of mechanical issue with their motion so with they leap or crow-hop (again the true crow-hop is super rare).
It isn't like they were trained to leap or crow-hop and have mastered the art and have a meaningful advantage. This is how softball games get played every weekend. Umpires, coaches, TDI, no one cares. The main reason no one cares is it isn't a meaningful advantage.
The only people that care are the hitters on the other team (only if they lose). The opposing pitchers' parents grumble as well (only if they lose from what I have seen).
I am not excusing the behavior, I am just trying to explain it.