I agree that for the same effort more weight bearing will result in more calories burned. But it is a discussion forum not "just answer one question"

What I have been trying to explain (not doing a good job for some), is that when we swim (especially triathletes) we actually use more energy than we think because swim easy effort is much harder than going easy in the other sports, because swim has this minimum effort, and over time, the load from that adds up. So three workouts at the same intensity, I agree with you. I guess I was trying to explain over many hours in a week or a single long swim like at the start of an Ironman, most triathletes likely use their highest average energy in the swim due to how difficult easy swimming is.

Now that I look back and I look a the OPs original question, I know why I embarked on this slant. Its because he asked "on average between all intensities". So it lead by down that discussion. My response was not meant as a competition about who is theoretically most correct. I was trying to relate this to the practical world for triathletes who may underestimate how much the swim is draining them overall.