#2 There are more deserving women on the roster
When this match was originally made back in May, Rousey herself pointed out that there are many more women on the roster who are much more deserving. Many of these women will be competing in the Money in the Bank ladder match and putting their bodies on the line just for a chance to fight for that title, whilst Rousey has done nothing to prove that she deserves the opportunity.
Rousey stole the spotlight from the first ever Women's Royal Rumble back in January and now she's been given a free ride to the Women's Championship match as well, which could be why many of the women backstage are said to be unhappy. Whilst it could be argued that Rousey is a draw and this is why she has been given these opportunities, she should still be forced to work for a chance at the Championship like all the other women.
Rousey said herself that she wanted to be treated like any other wrestler, but this isn't the case.