First of all, there are some easy questions to answer: 1. Were the comments made sexist? 2. Is sexism acceptable? The answer to the first is clearly Yes; they called into question Sian Massey's ability to perform a role based entirely on her sex. The answer to the second question is, for me, at least, No. I say for me at least, because for some it obviously is. Fortunately, the law also happens to be.
With the above in mind, the only real avenue that can be explored for their defence is that their comments were made privately, as far as they were aware. They did not intend for their opinions to be broadcast and were unaware they were being recorded. It seems like a reasonable course of defence at first but really, it's nonsense. If I were to steal your wallet and not get caught, it would still be theft and were I unlucky enough to be caught I would need to be punished. The issue of whether or not I intended to get caught is irrelevant. The same rule applies here. Yes, they were unlucky to get caught but now that they have been, they need to be punished. A suspension seems pretty weak in my eyes. Sky need to be brave enough to make a stand and make real examples of both.