I feel similarly, not about this charity in particular, but many others I have sent small sums of money (I have a very low income) and have sighed in annoyance to find that more money than I ever sent has been spent sending me further letters asking for money.
Personally I cannot really understand the "event" element of charity either. Someone does a parachute jump, people give money. The jump doesn't raise any money, people raise the money. I object to giving to the person who rattles the loudest tin, or bullying into giving money to a cause that is large enough to have "a day" - all children in class 2a will bring £1 for Children in Need - why? I see other charities I would like to give my money to and I will give it by choice, not because Mrs Thingie has decided we will all give a pound, and then the SCHOOL will be thanked for their fundraising, not the parents who actually parted with the cash!
Of course, if you could specify you wanted to give but only if all the money were spent on specific projects and none went into begging letters then who would provide the money for the letters? Nobody. And some people don't see a charity until they see the loudest tin rattling in their faces. Many will give to ill-defined projects such as "help the sick children" - help them do what? Get better? Get equipment? Continue their education? I don't like to respond to articles saying give to Charity X because this starving child needs you if I know the charity also has other interests, as I may not actually help the starving child at all, so I tend to donate to small charities with specific interests and identifiable projects. But it's even harder to do that and not give £x a month (I don't have a reliable income) or be chased and chased for more money. I already gave what I can/want to give, if I had more you'd get it already, stop asking! It's just a waste of my donation to harrass me to give more.