Indeed, if we had an article on [[Gerbilling]], no doubt one of our selfless editors would provide a photo of the activity that'd be stuck front & center. It's just not very relevant to Gerbils, which is why it's not there.
Yet if I put a picture of a gerbil against a cloudy sky in the article on gerbils, nobody would say "clouds are irrelevant to gerbils" and take the picture out until someone removed the clouds from the picture. Relevance isn't enough; offensiveness matters.