It's not easy to be "hard-core" eco friendly when it comes to scuba diving. Customers want to see creatures and part of the guide's / DM / Instructor job is to look for those creatures and point them out to those divers. Some animals are hiding under ledges, rocks and coral heads, others are living in / on live corals making it difficult or nearly impossible to point those out and yet still other animals live in burrows in the bottom and tend to disappear quickly when you come close.
Guides, DM's and Instructors use different "techniques" to show different kinds of creatures to their divers and many of those techniques are not very environmentally friendly towards the reef and the creatures on it. Unfortunately without using those techniques there often will be very little chance for a group of divers to see such creatures. Many divers want to see as many creatures as possible during a single dive and are unwilling to spend more than a minute or two with a creature at a time. Many divers also do not seem to know where to look or how to look for creatures themselves putting even more pressure on the guide / DM / Instructor to find and show the animals to them.
I think searching for animals and even teasing them doesn't do any harm. Opposite: if that brings enough money from tourists, the people are interested to keep the fishes there to attract tourists.
A bit sad that most DC in Thailand are owned by foreigner so that effect isn't as strong as in other countries.
Sad what you write about the Burma Banks!