I'd like to cast a vote on the side of the candy-a$$es.
I've just finished a week of delightful boat dives here in Cozumel at the Cozumel Invasion with Dive Paradise. Our DM (Martin) was great because he took responsibility for the welfare of the entire group at all times--on the boat before the dive, in the water during the dive, and on the boat after the dive. He was always looking back and making sure we were okay. He would frequently make suggestions about things like finning style, adding or subtracting air from BC, swimming shallower or deeper, etc. If I ever started looking around for my buddy (yes, I shouldn't have lost track of him in the first place, I admit it), Martin would ring his bell and point to my buddy. So he was always aware of what was going on with each of the 8 divers in the group at all times.
I would never want to go on a group dive with a DM who thought his only responsibility was to point out interesting sites, and who made no effort slow down if the group were falling behind.
Regarding the 2-year hiatus, I've seen dive ops where a refresher dive with a DM is a prerequisite before you can go on a dive, if you haven't dived in a certain length of time. The dive op in question here could avoid the problem of people not being up to snuff by just requiring this.
Since I rent BC and regulator, they're always attached to the tanks by the DM's. If the DM told me to attach my own, I'd wonder what that was about. In this case, they wanted to see if the divers knew what they were doing. Well, in that case, perhaps it would be good to be up front about it. "You haven't dived in 2 years, and I want to make sure you know what you're doing. Would you please set up your gear, I'll watch you and give you any pointers if you need them." Something like that.
But from the response of the dive operator, it sounds like she was angry before the boat left the dock over the divers refusing the refresher course. There's one thing I don't ever want to have, and that's a DM who's pissed off at me before we even get in the water!