Earlier quoted context omitted.
The most recent time, because they sent me a deluge of junkmail. They seemed to have morphed into a marketing organization that also did some legal work. Maybe the problem was that I gave them more than the normal amount of money; maybe the more you give them the more mail they send you.
Actually this is a huge problem that regularly deters me (and my parents) from donating more. 95% of organizations view a single donation as an all-access pass to send junk mail, emails, and in many cases even phone calls with "updates" and requests for more money. Sometimes I want to be able to say to organizations: "I would love to support your cause, but not if it means I have to deal with all your crap afterwards…
I think that's just going to leave me donating money to my alma mater, which actually has to worry about it's overall budget (in a lot of non-profits someone's making serious money sending out all that stuff, e.g. the NRA's PR firm has outright captured it in a weird twist on public choice regulatory capture).