Their results highlight a bias to turn heads to the right when kissing for both the initiator and the recipient of the kiss, and also that men were about 15 times more likely than women to initiate kissing.

15 times? That's interesting. Might also have to do with size differences (it's easier for the taller partner to initiate a kiss than the other way around. Men are usually taller)

In fact, when mirroring each other's head movements on request for a kiss, both the kiss initiators and the kiss recipients reported that they felt discomfort kissing in that way.

Well...yeah...Noses, ya know?

The researchers suggest different hormone levels

...or it might just be that you do it once (where handedness, as they note, is a deciding factor for the initiator) and then stick with what works? Unless they inject people with hormonoes to the left brain and then see a difference in behavior I don't see what they're suggesting, here.