It's a seller's market, don't take a job at a company with policies you don't agree with, regardless of how common they are or how enforceable they might be[1]. It's quite easy to find employers in the bay area that don't demand such things or will waive the clause.
Make sure to tell them why you didn't take the job.
[1] I suppose if it's clearly and completely unenforceable little harm is done
In some cases --- maybe a lot of them --- the board of directors requires the management team to operate from an approved boilerplate contract. I'm sure you can get anything overridden, but I wouldn't fly off the handle just because I saw an agreement like this.
are you speaking from experience? if so, i'm curious - is it that you confined your search to boston, or that people elsewhere were unwilling to relocate?
Make sure to tell them why you didn't take the job.
[1] I suppose if it's clearly and completely unenforceable little harm is done