The quote that you give implies that showing that you are getting "credit" for a mitzvah is an insult to the dead person who can no longer do mitzvos. This can be considered that the mais cannot do any mitzvos whether the person was chayav in it while alive or not. A woman is not chayav to wear tzitzis but is not forbidden to do so. Thus, it would still be "a subtle mockery of the deceased who can no longer perform" any mitzvos at all. This is a matter of logic based on the Tur and the Shulchan Aruch shown below.
Note that the Tur and the Shulchan Aruch are speaking of someone in a cemetery. However, the fact that they do not differentiate between men and women or mention the case of a dead woman at the funeral home seems to imply that this applies even to women.
Tur Halacha 23 Seif 1 explicitly says that because we do not normally wear tzitzis on regular garments (but just for the mitzva) would be asur to wear tzitzis in any case because to the insult to the dead people. He does not mention wearing the tzitzis covered at all.
Shulchan Aruch Halacha 23 Seif 1 says that it is asur and does not differentiate between a man and a woman.
... these words apply only if they are "open", but if they are covered, it is mutar.
This is repeated in the Biur Hagra and the B'eir Hataiv in order to state that it also applies to tefillin.
However, as @DoubleAA points out, while this appears to be the case (from logic) we actually see from
משנה ברורה על אורח חיים כג
אבל בקבר אשה דבחייה ג"כ פטורה ליכא משום לועג לרש
But at the grave of a woman who was patur even while she was alive, it
is not considered demeaning.