My advice is to immediately rebrand as gracefully and effectively as possible and use all that activist energy to effect the transition.
They kind of have a point which doesn’t make them right, but they hold all the cards and you will lose this one and regret the wasted bandwidth.
In this case, the complainer had several important details on their side: Apple had previously featured the app, the rule that they said was violated wasn't violated, and they tolerate other apps which violate those rules. It seems likely Apple realized in this case that it would be easier to keep the app since it's not like the app was ruining their family friendly image (although many people, especially in the US, picture the negative effects of methamphetamine additiction when they hear "amphetamine", amphetamine is actually an approved drug used by many in the US).