The ability to create arguments for either side is fundamental to "debate club" and what passes for national news media in the United States. Indeed, both groups are quite skilled at insisting that all issues have exactly two sides, which are completely equal in merit.

I can't see much reason to value the exercise in light of such an astonishingly BAD track record...

I do believe it's important to see how easy it is to rationalize something, it's just not useful to practice (unless you're looking to do writing or some other endeavor where "what if" scenarios are actually an important skill)

Speaking from my own personal experience, I can explain away ~90% of plot holes in kids cartoons as being completely reasonable. (Percentage calculated based on my friends having genuine "okay, wow, that makes sense - you're so smart!" reactions.)