This is another instance of the attempt to make sex distinctions not matter in a liberal society. It is now considered bad form to write words like wife or lady. These words are gendered and are therefore to be replaced in 'correct' usage.
Lawrence Auster's explanation of why a liberal society can't tolerate sex distinctions is very good:
But why, as I said in the title, must libertarianism, including the hip libertarianism that has always been touted by Apple, turn into PC? How does the belief that we are all free individuals, with no higher entity or authority telling us what do or how to be, mutate into a mad leftist authoritarianism that seeks to banish ordinary words from our language?
It's not hard to understand, but few conservatives and even fewer libertarians understand it. If we are all free individuals, with no authority above us, belonging to no collective categories to which we must conform, then any attribution to us of features or qualities that do not come from our individual choice, such as our sex, is an imposition on us. It violates the core liberal and libertarian principle that we are free, undetermined individuals who choose our own values. In order to be truly free, we must be equally free. And in order to be equally free, we must all become, insofar as possible, sex-neutral beings. Thus Apple's hyper feminist proofreader.
...Again, if you believe that individual freedom is the highest value, then you must also believe that there is nothing higher than individual choice, which in turn means that any larger cultural, biological, or spiritual categories to which we may belong are illegitimate and unjust, because they place limits on our individual choice.
I also liked Jim Kalb's comment in the discussion:
if you choose anything more restricted than the common good as the highest standard in politics, the favored goods (in this case, a particular understanding of freedom as neutral treatment of the goals of individuals) will end up destroying non-favored goods that in a more rational system would be balanced against the favored goods You'll end with something oppressive.
In other words, politics should be about the balancing of a range of goods. There is no magic formula for getting this right - it's a matter of wise leadership, learning from the past, thinking through the logical consequences of policies and so on. The better the balance, the more successful in the long run that society is likely to be.
If, on the other hand, you make just one good the overriding principle (which in a liberal society is the principle of maximising individual autonomy) then other goods will be either banished or neglected or, at least, not taken seriously enough as public goods to be sustained. The end result isn't freedom or individual flourishing but an intrusive state (it has to be intrusive to suppress the non-favoured goods) and individual alienation (as the larger connections in society have been broken in favour of the sole, overriding good of autonomy).