You label this a “standard leftist critique,” but you haven’t pointed out why this critique is invalid. You imply it doesn’t hold water without actually providing an argument against it.
Whether or not the critique is valid, the action of criticizing can be invalid here. It is similar to how yelling, “fire!” in a packed theater is rarely the correct way of transmitting information about flaws in the world around you. I think most people would appreciate an explanation for why you are suppressing potentially true free speech, but the explanation does not necessarily need to come paired with the suppression. So, you can have something like this occur:
Alice: I think we ought to overthrow the government.
Bob: Shut up!
Bob may be worried about others overhearing this and turning them in, even if he agrees with Alice. But he can’t say that, at least not in a public forum. I think the issue with “standard leftist critiques” is that these memes are highly virulent, and most people are not innoculated against them. Systems are hard to fix, so people who have been infected with these memes—even if they are true—may take worse actions than if they had never heard the critique.
Perhaps I’m missing something you’re saying, or you’re missing something I’m saying. In general, the process of finding a “conjugate space” is not an involution. We do not have inner products or Hilbert spaces. There are no pairs. We have to motivate the inner product, and it is motivated by first motivating multilinear forms, and then motivating bilinear forms. But bilinear forms only arise in the alternating representation.
There is a terminology issue here, because “dual” literally means a paired, mirror space, so treating the inner product as a bilinear form in a space ⊗ its dual only works in the alternating representation. What you’re actually doing to generate that dual space is to look at the connected components of
{A:ρλ(A)∈Im(πλ)}.
For the alternating representation, there is the component connected to the origin—SO(n)—as well as the mirrored component J−1SO(n)J. But there are many more connected components for other representations, exactly |Im(πλ)| of them. Maybe some of them have involutions to each other, but not all of them. Not all of them are “dual” or “conjugate” in the literal sense of the word. This is the terminology issue, and I think the main source of confusion.
Also, my analogy does not break down for odd n. Note that Vλ is an irreducible module of (Cn)⊗n, not the same space, and (Vλ)⊗k is an entirely new tensor product. I was trying to keep my comment from growing longer than it already was, so I may have left out many other little details like this that would help with interpretation.