In a book of wordplay called Wordbirds: An Irreverent Lexicon for the 21 st Century, Liesl Schillinger humorously defines a mute point as follows:
“When somebody in a group makes a good suggestion, but somehow nobody hears it.”
In a similar vein, Urban Dictionary defines it as “addressing the participants of a conference call while your phone is on mute.”
Fans of the TV show Friends may have heard a third variation: moo point (because, according to Joey, a cow’s opinion doesn’t matter).