Ben- At first appearance this seems more laid back than normal. Everywhere I've dived I've been asked to show the card, including where I got my nitrox & rescue certs. years ago. Failure to do this basic due dilligence can be a sign of a sloppy operation.
Other than that, it might (that's MIGHT giving maximum benefit of doubt) not be as bad as it seems. The other divers might have had prior dives & the divemaster might have known that they were buddy pairs. In fact the DM did stay close & was there as backup for you. It would have been nice if he told you he was going to be your buddy, and if he had asked if you've ever done a back roll entry.
In the end, all's well that ends well, but there's a lesson here for you. It's your responsibility to take care of yourself on dives. That's what certification is all about. You need to be clear & firm about things that affect your dives, and not assume that someone else would sweat the details.
For example, the DM did stay with you, but what if he hadn't? YOU should have made sure beforehand that he, or someone else would. YOU should have asked if there was anything you needed to know about back roll entries, or any other aspect of the dives.
In the final analysis, you need to know that you'll encounter a broad spectrum of diligence as to dive operations in the future and you & only you, need to take care of yourself. Don't assume anything, & don't wait to ask questions until you're 10 feet underwater.
I know it's hard to be insistant as a newbie, but the bright side is that your instincts are OK, and with a little more self confidence, you'll become a better, more outspoken diver. I'd be happy to dive with you anytime. dF