IMHO, boycotts are poor stewardship.
I could be doing something productive in the time it takes to keep up with all of them.
You know, Amazon contributes 5% of their online sales to me too, when the sale is made though a link on one of my sites. Same thing as described here. I'm not sure this can really be called a 'contribution', it is a 'commission' - a percentage of sales generated.
Tempest in a teapot.