I tend to think banning gloves and knives is an easy, cheap and ineffective way of protecting the reef, because the kind of people who will grab the corals and cut things with knives will probably do damage anyway or ignore these rules, and instead, the people who get inconvenienced and/or upset are not the ones causing the problems.
That said, I don't wear gloves in the Caribbean and carry a small line cutting "rescue hook" as an emergency cutting tool, instead of shears (personal preference), so I am not inconvenienced by the rules in Coz or Bonaire.
As far as buoyancy checks, I see two problems:
1. I have seen people who have no regard for the health of the reef and many (most, perhaps) of them have been very experienced divers, including instructors. I don't think buoyancy checks would help either, as these people were capable of avoiding damage if they had cared.
2. Buoyancy checks would identify divers with poor skills, but then what? Tell them they can't dive? Keep them 30' from the reef? Take them only to sandy areas? Make them take a buoyancy course before they can dive? This would cause a tourism backlash that would cause a loss of tourism dollars. I doubt we will see that happen.
The knife/gloves rules are probably silly, but no one asked me first and I don't have a say in how Mexico governs its waters. My feeling is that each of us should follow the rules or choose not to, but if you don't follow them, don't complain if you get hassled or refused a dive by a DM or punished by the the reef police or whatever.
That is kind of how life works.