Awakening,
The hypocracy and half truths are the issue. If you go to the other thread that was linked, i think the most succinct question is provided by OOdad. He posts two letters side by side. one by the brach explaining their side, and a letter by the DPI explaining theirs.
Once again, none of this would be an issue if the branch did not take a dogmatic stance of their own. They used to (don't know if they still do), say joining he YMCA was joining an apostate organization which you could be disfellowshipped for. Now if you pay membership to the YMCA, you don't get to help RUN the YMCA. You just get to use the facilities. Basically exactly what the branch is saying they did.
So why then, even by their own reasoning, would they think its fine for them to visit the library and avail themselves of resources down the street at wild beast headquarters, if Jimmy JW can't join the Y to use the basketball courts?
I actually think it is possible that someone acted innocently enough, and nobody thought anything of it. I think most JW's don't see this as a major issue. But that is because they don't understand the hypocricy based on the standards they have set forth for their flock. So your elders response that it isn't a big deal......sure I get that. But he hasn't consider why someone would be within their right to go ahead and consider it a big deal. he may "research" it, find the letter from 2001, and it will 100% satisfy him. You have to bring out the YMCA hypocricy. its the only thing that gives context when dealign with someone who decided it wasn't a big deal before they even knew what it was.