[lelio]

This doesn't necessarily imply that these companies support HCI. progressivefunds.com looks more like a clearinghouse for referrals, where if you click on one of their links the company you bought something from will pay progressive, which will then pay the non-profit that listed the company.
A company might not even know who ProgressiveFunds is paying out to, but they could peruse the site to see who they want to be associated with.

[glockmeister40]

At the top of the web page it states: "raise money for handgun control, inc. every time you shop online". I believe this means that when you buy from a listed merchant, they give some money to HCI. To me, giving money implies support.