I've participated in a couple of Masters swim programs, and I enjoyed them. But I know how to swim--all the strokes. The Masters programs are not geared to teach you strokes, just improve your fitness and technique. And knowing different strokes is important. It's a very athletic and competitive environment, akin to fast club rides where cyclists do pacelines. Not a place to learn new stuff.

The coach sounds like a snarky jerk, but there are all types. Yes, it would be nice if he were up-front and told you that either he you are in the wrong place or work with you to get to where you are more comfortable in the water.

Taking some swimming classes would be really beneficial, and then doing workouts specifically for tri training. You can determine if you want to join another Masters program at a later date.