That would make sense if, say, any phrase in square brackets was the reason for the rejection. The fact it appears to be only "no ads" means that clearly isn't the reason.

The alternative is Amazon style titles which contains insane amount of details (because that is/was the only thing Amazon could search).

Ideally Google would allow the apps to be tagged as free, freemium, paid and app supported. I suspect part of Google reasoning is that doing so kill almost all the apps supported by ads.