I don't mind them having that and honestly, I haven't really noticed much more junk mail than before. I get about a million credit card offers, but I received those before Swagbucks. The only mail I think I have ever received in relation to offers was for stuff I paid for, charities (after donating to one through Swagbucks), and a few free samples. I've received the colored diabetes and MS Awareness bracelets from Quality Health, some vitamins, shampoo samples, etc.
Edited to add:
Actually, all of the free offer related mail I have received has actually been kind of cool, since it's free samples like I stated, or for the charities that keep sending me mail looking for more donations, I've received free address labels, stickers, window decals, notepads, greeting cards, and even packets of seeds. All useful things. Although, it has made me rethink donating to certain charities as it seems a fair bit of donations end up paying for the free stuff they send out.