Of all the topics of liturgical concern…
This is a very subtle form of iconoclasm, IMO. But its a straw man issue at best. As silly as it would seem to demand choristers to imitate the images of frescoes and mosaics showing angel choir hosts in flowing white gowns carrying lyres, it is equally pointless to critically obsess over whether a choir accessorizes their clothing in liturgical colors appointed for a particular feast day or choral event.
I remember adjudicating a collegiate choir festival decades ago. Each ensemble save one had beautifully chosen gowns for their women in various tasteful colors to match the men’s tuxedos. Then a “lesser endowed ($)” choir took the stage. The men did wear tuxes, but the women wore floor length black skirts and long sleeve (satin) blouses of all the varying primary and blended colors. The effect was stunningly wonderful, and in its way, reminded everyone that uniformity as well as beauty is in the eye of…
I’d suggest we pay more attention to the internals of what our rituals mean (which I happen to think is what HHFrancis is sharing in his daily homilies and addresses to clergy and lay alike) rather than whether a baritone, lector or EMHC wears purple ties during Lent.