Sorry to hear of your moped ordeal......now that that point has been made, it has always been advised by the cruiselines to NOT RENT MOPEDS on any island, period. It is a risk that you take for your safety as well as those possible "rip off businesses" as you so gracefully stated.
As for your "BROAD" paintbrush stroke made against mexicans...... Have to disagree with you and think you should retract that racial statement. In all my experiences when travelling to COZ, and I travel to COZ 2 times a year either by ship or an all inclusive land package I have never had a problem with their vendors or their "culture/nationality" when staying at hotels, dining out, shopping and renting "vehicles", but I also make sure I take out full coverage insurance just in case !
Sorry it did not work out for you, but there are many folks that really like COZ... you just got soured by a bad moped experience (your decision despite warnings onboard and on many cruise boards). As for some dirty ocean water at the beach.... I would hope that you know that this does occur when storms or high seas have churned up the water at any caribbean port of call....not specific to COZ by any means !
No need to make the nasty remarks you did about mexicans though just because you had a less than positive experience