If Sam and I are engaged in some activity A, and Pat comes along and punishes Sam for A or otherwise interferes with Sam's ability to engage in A...
...if on reflection I endorse A, then I endorse interfering with Pat and aiding Sam, for several reasons: it results in more A, it keeps me from feeling like a coward and a hypocrite, and I establish myself as a reliable ally. I consider that one of the obligations of social alliance.
...if on reflection I reject A, then I endorse discussing the matter with Sam in private. Ideally we come to agreement on the matter, and either it changes to case 1, or I step up alongside Sam and we take the resulting social status hit of acknowledging our error together. This, too, I consider one of the obligations of social alliance.
...if on reflection I reject A and I can't come to agreement with Sam, I endorse acknowledging that I've unilaterally dissolved the aspect of our social alliance that was mediated by A. (Also, I take that status hit all by myself, but that's beside the point here.)

I really like your illustration here. To the extent that this is what you were trying to convey by "3)" in your analysis of wedrifid's style then I endorse it. I wouldn't have used the "alliances" description since that could be interpreted in a far more specific and less desirable way (like how Wei is framing it). But now that you have unpacked your thinking here I'm happy with it as a simple model.

Note that depending on the context there are times where I would approve of various combinations of support or opposition to each of "Sam", "Pat" and "A". In particular there are many behaviors "A" that the execution of will immediately place the victim of said behavior into the role of "ally that I am obliged to support".