Is it an advanced sexual topic when a hetero married couple, like a child protagonist's parents, have a similar quick peck on the lips? Because if so, that seems overly prudish, and if not, the people who have a problem with it can grow up. To my knowledge, having not seen the movie, that kiss was really only showing that they had someone important in their lives, and I know that Bo Peep could get away with kissing Woody in Toy Story 1 with no controversy at all. There's also still politics within Monsters Inc and Finding Nemo without looking very hard, and I seem to remember the extremely political Wall-E being wildly popular with audiences and critics, even if I didn't care for it.
WadeTheWizard