Share me your sight for this kind of scenario:
A dev create a token, for a scam attempt, wherr they'll get listed in an exchange and dump everything and leave. Normally, they'll find it difficult to get an exchange due to listing procedure, etc. But thanks to your service that, as you mentioned, allows every token, now they can PnD freely.
In order to use our service, developers will also need to go through the listing procedure. Payments will be possible only by those coins that will be on our exchange. Therefore, the scenario you specified will be minimized.