Not sure the point you are trying to make here, but if you couldn't manage the small list of exclusions for UOB PPV/VS (or Citi, or HSBC), I'm surprised you could manage DBS's own list of exclusions.
These same issues exist while DBS was still giving out points for this card, so I'm not sure how DBS excluding all Amaze transactions from rewards make this a problem now.
Frankly, if you have an issue with the way the card works, that's fine. Nobody is saying it is perfect. The arguments you raised are well known, even when DBS was giving points (well, except for the 'wrong MCC' argument. I've no idea what that has to do with Amaze). But if you are going to argue that it is useless come June 1st just because one bank is no longer offering rewards for transactions through the card, you need to come up with arguments other than generic problems with the card.
By his theory, better to just use cash. Safe from MCCs, & chargebacks.