The blog does come from company officials and so you can show it to a judge and state "this is how you should interpret their ToS". It will be harder than if the ToS was clear, but the judge on seeing the ToS and blog differ is likely to come down hard to Mozilla for creating this situation. But you also need a good (expensive) lawyer to pull this off.
Even with a lawyer it's still a gamble if you will win - and in either case, the damage will have been done by then and no monetary compensation will undo it.
