It is not on technical grounds. Firefox is a very good browser: flexible, able to be secured.
It is not because it is open source. This is a good thing.
It is because of ideology. It because the board of the Mozilla Foundation lacks the will to stand up to a heckler's veto of their choice for chairman, Brandon Eichs.
This is as bad as the Komen Foundation Flap.
The call to persecute and ban people from work based on ideology, especially the dysfunctional, short-sighted, amoral ideology that is behind the current LGBT acceptance at all costs is reprehensible. The push reminds me of the old "blacks make me feel uncomfortable" meme. Straights, especially traditional marriage supporting hetrosexuals, apparently impel some in the LGBT community to act in an intolerant manner. One might even use the words "shrill" and "hissy fit" to describe the reaction.
Disappointed is the best description of my reaction. This is a "food sacrificed to idols" issue. A browser is a browser. Yet, if someone goes out of their way to point out an explicit political stance taken by a company that is in conflict with what is right (and what most sustainable cultures have embraced) I must act.
At some point I too may be unemployable for political reasons.