Blunt and opaque? Isn't that like saying "hot and cold" or "black and white"? Yes, in the normal world. But remember that the world of The Handmaid's Tale is far from normal.
This is a tricky one—even though narrator speaks plainly and bluntly throughout the book, much of the time her words seem to cloak or obscure what really happened. The contrast between what's being revealed and what's being hidden is formally emphasized by the slippage between what characters say and what they think.
From a technical standpoint, we can see this in the absence of quotation marks to separate speech from thoughts and feelings, particularly in memories. For example, consider this excerpt, in which the narrator flashes back to a disagreement she had with Luke when she tried to explain to him how being stripped of her agency in society has made her feel:
You don't know what it's like, I said. I feel as if somebody cut off my feet. I wasn't crying. Also, I couldn't put my arms around him. (28.86)
This conversation takes place in the narrator's mind, so we have to take her word for it that this is how it went down. Here the book moves rapidly between what the narrator says to Luke, first "You don't know what it's like," then "I feel as if somebody cut off my feet."
The second statement could be an internal thought, since it overlaps with "I wasn't crying." The narrator then immediately shifts to what her body can't do: "put [her] arms around him." She can't put into words "what it's like" for her, and she can't act on her feelings. Her body is defined by what it can't do: cry or hug her husband.
So there are facets of this argument that we can't see. Its lines are blurry, and the narrator reinforces that blurriness, but she also doesn't shy away from the tough moments in her text.