Charities generally drive me nuts, too. I especially loathe the cold-call ones. I have a standing policy that any charity that calls me without my prior approval never gets one red cent from me. Likewise I will not have anything to do with "charities" that are thinly veiled Christian organizations bent on spreading their religion to other people. I notice they looooove to use soup kitchens etc for this purpose. Real hard for starving people to say NO to unwanted religion crammed down their throats.
I do not donate or buy anything from the Slavation Army for many reasons, not the least of which is their discriminatory hiring practices, basically if you aren't a hardcore protestant, bugger off. Since I'm Pagan with occasional lapses back into Atheism I refuse to support that kind of organization.
There's another charity in the guise of Christianity in the industrial area I work in, I had to poke around their website to find out it's related to their religion. They aint getting **** from me.
If any canvasser etc knocks on my door I will call the cops, it would be trespassing. My door is accessible via the backyard.
My Gramma etc tried to cram Christianity down my throat when I was growing up, I eschew it.