I, too, always questioned this irrational stance on Charities.... the biggest irony being they themselves deem to be one!
Back in 1992, I got involved with a group in our office who went to Romania to take some relieve goods to an orphanage in North West Romania, Satu Mares. There were four of us who made the trip in two vehicles. We made appearances on local radio etc, - doing all sorts of things locally to collect together relief donations. In the end we had collected around 15 tons of aid. I pondered at the time whether I was doing the right thing after I receieved 'counsel' about what I was doing. I countered by saying, "just show me one thing that is wrong about helping those less fortunate than us?" As you can imagine, I was looked down upon but I still did it. Quite an experience in itself!
Anyway, my parents frowned upon my activity (I was 40 at the time with 3 kids) but nothing was going to deter me - I was feeiling good about what I was doing. After my return my mother said the strangest of things. "I'm glad you're back safe. Now, I can at least say to critics in FS when they moan about our lack of charitable works, that they are wrong. My son went to Romania with relief goods." She was proud of it too.
It's as if many JWs have a conscience about this but can't get themselves away from the controlled mindset. Surprise, surprise!