Is this a psak halacha, IE it is ASSUR to name your daughter Shira
(or the other names listed in sefer), or is he saying there is an inyan (that he may understand that we do not) not to name your daughter or to specifically name certain names?
If for example, someone davens to hashem for a child and after many years their tefilla is answered, and they want to name their daughter Eliana (contraction for Keli Ana – my hashem has answered me) is he saying ASSUR? If someone wants to name their child after something that inspired them, is that ASSUR? Most names found in tanach were given in exactly that way. My gut feeling tells me that it is not ASSUR to give the name Shira and the like, rather there is some inyan not to do so. There may be an overriding inyan to name your daughter Shira. Ask your Rav.