You pay for a license to use the recordings. I’m sure the proper fees were paid for use of all musical recordings.
The whining by the artist is symbolism, their permission is not required to play the music.
I'm pretty sure if it is played on TV, you do. It's called a Synchronization and Performance license. The publishing company can deny such a license.
It's different than recording a cover on a record--that's called a mechanical license and it's automatic by statute. Also "grand performance" rights give you the right to sing someones song in a public performance (but not on TV). It's possible that, since this is a newsworthy event, the media is able to transmit the event under fair use. So the grand performance rights would give the right to play the song at the convention and the media would have a separate right to broadcast anything that happened there.
It all depends on who owns the publishing rights to Heart's "music." I doubt the girls own it--its probably the publishing company associated with the record company that Heart recorded for.
Take all this with a big grain of salt. It's been more than ten year since I practiced law and there's a new copyright act since I was acquainted with the field.
If they're pro-abortion feminists, they're likely horrified that their song is being used for a Christian, pro-life woman! ;o)
There much better. Go away now Ann & Nancy. We have are own talent in the conservative party.