No, I've never purchased anything Purina. No, I've never given money to the Salvation Army (not that I agree with your claims, I've never researched their supposed anti-gay position). You might have to dig down to where I buy my shoe laces.
Your position proclaims that if all things apply, then nothing applies (that is your point, right? that everyone is guilty, and thus anyone pointing fingers are just hypocrites). In reality, all actions and beliefs are not created equal. Even in a world of glass houses, some stones are dramatically more destructive than others when thrown.
A very large portion of morality is based on intent + knowledge / awareness. Someone that buys shoe laces from an anti-gay business, while not knowing that fact, is not morally guilty of supporting the anti-gay movement, even if they are financially guilty.