Because BMW designed it badly and their testing was not rigorous to catch the failures. BMW's DI engines had the carbon buildup problems by 40-50K miles and needed walnut blasting, bad design and testing. Mazda Skyactive does not have that problem, good design and testing. Simply because BMW users reached some conclusion does not mean every one and his uncle blindly follow suit.Well, that's the conclusion a bunch of BMW owners came to at e90post and their transmission has the identical pan filter design as our cars. Just because you are unsure of something because there is insufficient information on your part to confirm otherwise, does not mean I am automatically wrong with my logic.
Explain why else Mazda claims the transmission fluid is "lifetime" fill, but allows an overly complex procedure to change your pan/fluid along with the necessary parts and fluid to do so.
Mazda's transmission oil/filter change is not as easy like enginer oil change because it is not required to be done regularly. It does not mean there cannot be a rare occasion some leakage/breakage/malfunction happens that needs oil/filter change. Common sense buddy. Just because it is complex to get to something does not mean the specific intent therein is it will never ever go bad and there is no need to get to it ever. There are a lot of hypochondriacs here who will overdo stuff, that's their problem.