If we are talking about precision, wouldn't Species then be the superior choice? Ancestry makes sense when you look at what you came from, half orc, half elf, aasimar, tiefling- they are all human or human based, for example. Orc would be a separate species entirely, cross-compatible though the two are.
I'll admit, I am new to Pathfinder, so the different species are unknown to me.
Honestly, I'm seeing a lot of extreme views from both sides.
Some are saying you should hard-line stop at offense and shut all of it down immediately, while others are swinging the other way.
Shouldn't you slow down and discuss it with the player(s) in question? I mean, if neither are going to move and said player is going to be disruptive, or the GM is gonna be bullheaded and ignore the player(s) then a change in table is in order.