I think that perspective is needlessly individualistic. You can take a view that something isn't in someone else's best interests. The bigger issue with Mozilla is that people feel it represents them, and it does in its lobbying for the the open web. If it is led and represented by someone who you feel[0] is opposed to your very being it is hard to imagine it representing you and easy to see how you could oppose the appointment.

[0] Some may see opposition to gay marriage as opposition to homosexuality. In some cases this is probably the case in others it may not be.