Of course. Which nullifies any argument about whether it is Yes-in-my-back-yard or yes-in-your-back-yard. You only get to make that distinction if you're talking about your own literal back yard.
I think this comment is accurate just from a logical standpoint. Backyard has two possible meanings here:
* Literal backyard: in this case, then maybe one could argue that if we accept the premise[1] that YIMBYs aren't homeowners, then they are in fact arguing about other people's backyards.
* Figurative backyard: in this case, then whether someone is a homeowner is irrelevant, because the backyard refers to the general area, shared by all residents.
Of course, as we know from this thread, backyard in [N|Y]IMBY refers to the figurative backyard. Therefore, we must reject the argument that people are arguing over other's backyards.
[1]: As I argue elsewhere in this thread, I don't think we should accept this premise.