Yes, I agree that we're much more confused about subjective experience than we are about containership.

We're also more confused about subjective experience than we are about natural language, about solving math problems, about several other aspects of cognition. We're not _un_confused about those things, but we're less confused than we used to be. I expect us to grow still less confused over time.

I disagree about the lack of comparable cases. I agree about containers; that's just an intuition pump. But the issues that concern you here arise for any theoretical construct for which we have only indirect evidence. The history of science is full of such things. Electrons. Black holes. Many worlds. Fibromyalgia. Phlogiston. Etc.

What makes subjective experience different is not that we lack the ability to perceive it directly; that's pretty common. What makes it different is that we can perceive it directly in one case, as opposed to the other stuff where we perceive it directly in zero cases.

Of course, it's also different from many of them in that it matters to our moral reasoning in many cases. I can't think of a moral decision that depends on whether phlogiston exists, but I can easily think of a moral decision that depends on whether cows have subjective experiences. OTOH, it still isn't unique; some people make moral decisions that depend on the actuality of theoretical constructs like many worlds and PTSD.