I mostly agree with you, but I need to be a bit pedantic and point out that a boycott is voting with your wallet. It's better, actually, because you vote with your wallet and tell the publisher that you did and you encourage others to follow suit. This way publishers can't just blame something else for the lack of sales for Generic 3d Shooter: Curbstomp Edition.
Well, there's a difference between participating in a boycott and "participating" in a boycott -- the first is voting with your wallet to not buy X (and telling the publisher publicly that you aren't), and the other is yelling and screaming that you aren't going to buy it, then ending up buying it anyways (see the MW2 Boycott Group who ended up having egg on their face: http://nerdnirvana.org/wp-content/uploads/2009/11/abXW9.png)
After participating in a few boycotts myself (and following through on what I said I would do, not just grandstanding), only to see companies continue to make record profits, its hard not to feel like you are fighting against the tide coming in.
