funny, If I go with a prostitute, according to Doubter, I just agree with her objectives but not with her beliefs/actions. UN is, according WT, a prostitute. Draw you own conclusion here.
Being a member of a political organization is a no-go situation for a JW. NGO membership with he UN is equal to being a member of the UN political organization. Not the same right as all others (oh how sad, as WT is soooo important) but still a member. Why else apply for a card? One drop of ink in clear water pollutes the entire glas of water.
Becoming a member of the soccer / football club is a no go for a JW as it might seem you support the objectives (competition) of that club. Being a member of the UN has exactly the same impact on people who see this. It means you support the UN, little or big, it does not matter. leaving a house of a single woman in the morning is immediate judgment, no matter if something happened.
point is that WT is obsessed to be recognized as being important. UN membership was one way to get that. Same with the OBSE in Europe. Why join? To feel important. WT is not important in the world at all. Actually nobody cares. If they would stop tomorrow, it would care nobody except for the current members.
Doubter is a typical JW. Blind and follows those who pretend to be angels but are actually wolves disguised as sheep. How can you recognize the wolves? Only if you open your eyes. Do I care if Doubter ever opens his eyes? No. His viewpoints? Useless. Same as JW's. they believe they are important and that their work are of major importance, with global impact etc.
I suggest to just ignore Doubter and treat him as the WT would treat anyone who disagrees with them. He is used to that.