I have used these "theories" in the past to see for myself. Every time... no change to gameplay. None, zero, nada. It simply is not true as much as people want it to be. I have been playing Madden since Madden games have existed. I have put countless hours into slider settings, isolating specific sliders (gameplay, penalty, fatigue, speed parity). I have done immense amount of testing over the years on player ratings in combination with a wide range of slider sets. Still, through all of that, I have never been able to get penalty sliders to impact the way the ai plays.
As I stated before and has been stated by others, there is nothing in the game coding to make this true. Plus the "logic" behind it just does not make sense. It is always argued, including in the posted video that the ai players act a certain way to not get penalties if the slider is too high on some sliders (such as def pass interference) and then having offsides high creates more aggressive behavior. The logic used on one slider does not make sense compared to the logic used on another.
This is no different than the theories that you have to set your settings in a certain way in the Main Menu and then have different sliders in Franchise mode and somehow the Main Menu sliders "bleed" through into Franchise mode and magically makes the game play better. That makes no since either but plenty of people swear by it and do it anyway.
Play the game the way you want, with whatever settings you want. But until someone can show me some definitive proof that penalty sliders impact ai players in some way beyond trigger animations and frequency of penalties, I simply will not believe it. I will take the word of people who work on the game code and the modders who have sifted through the code, as well as my own testing and observations, over what people claim to "see."
I am not trying to be rude or anything of the sort. I am merely trying to provide some logic to these claims that have been thrown out here for years. I have been in these forums long enough to see all kinds of wild and crazy theories out.