Although really the talking point itself is inane

One talking point that I've seen repeated a couple of times by people trying to deny the obvious parallels between the struggles for civil rights of blacks and gays is "There were never any heterosexual-only bus seats."

Which is true enough. Bus seats, no.

Entire buses, maybe:

A transit agency chief apologized Wednesday to two teenage girls who were kicked off a city bus for kissing each other.

The girls, both 14, said the driver called them "sickos" after a female passenger complained about their kiss. The driver then stopped the bus along the street and forced them off.