Let's look at the numbers:

99% of open source developers are men (http://people.cs.umass.edu/~wallach/talks/2011-04-05_JHU.pdf). It appears that women just seem to have better use of their time than writing code for free :) (free seems to be the operative word - not use of gendered pronouns in open-source vs commercial software world)

So let's mutilate english language (which is what referring to one user as 'they' really is - let's be honest) for the sake of some percentage of 1% (and probably larger number of men who feel bad for these individuals) who are unhappy to see a gender pronoun.

Now - I am not saying that one way is better than the other. I merely want to frame the argument honestly.