Yes, you do need a GET license. An incorrect number was printed July 13. I agree wholeheartedly with this person. I get demanding phone calls on Sundays as well as solicitors who come to the front door. Nameless I sympathize with the person who feels besieged by requests to donate to charities.
Charities share, sell and rent mailing lists.
If you donate to one, expect to hear from others. If you do not respond after a couple of times, most will not pursue you further. There is no need to feel guilty. You cannot support every worthy cause. Pick a few charities with special meaning and which have a good record of using most of the money they receive to meet needs instead of overhead costs.