Same-Sex Marriage, Boycotts, and the AALS Conference

From the National Law Journal (thanks to Mark Scarberry at Pepperdine Law for the pointer):

Organizations representing thousands of legal educators say they will boycott the Association of American Law Schools annual meeting in January if it is held at a San Diego hotel owned by a foe of same-sex marriage. . . .

The groups are the Society of American Law Teachers; the Legal Writing Institute; the AALS Section on Legal Writing Research and Reasoning; and the AALS Section on Teaching Methods. The groups represent as many as 2,500 members.

Several of us here, in varying degrees, emphasize the importance of, prima facie, letting people express their conscience in marketplace actions (landlords renting a few apartments, pharmacies refusing to dispense Plan B) without government interference.  We also emphasize the value and inevitability of people acting in groups, not just as isolated individuals.  So a boycott like this is legitimate, yes? -- but at what point should a "market power" counterargument kick in?