Is there any large group representing App developers that could manage the large-scale negotiation and legal wrangling required to force Apple and Google to be more helpful when rejecting legitimate applications? When I worked in Google (Ads, then later in Recommendations for Play and youtube) people often said this was intention to avoid teaching spammers how to get around the rules. But it's clear there are enough…
Abuse prevention is adversarial, and it's risky to reveal details about why something was flagged as abusive. Policy compliance isn't, or shouldn't be. A building inspector wouldn't say "this building has a code violation in the kitchen area" and refuse to provide specifics about what would fix it.
An app store needs both, and they need to operate differently.