I learned of tree shaking first, and DCE is clearly superior as a term: 1) it's actually descriptive, 2) there's a large literature using this term to look for further information, and 3) as the original poster noted, it's not actually a misnomer. There is literally no advantage to the new term that I can think of.
Tree-shaking is specifically the form of DCE where you remove unreferenced functions/modules.
Especially important is that you can do tree-shaking without analyzing control flow, while by default "DCE" implies you're analyzing control flow.
And I don't think tree-shaking is a misnomer. Depending on how you visualize the metaphor, unreferenced functions are either barely attached or not attached. Shaking them off is simple and sufficiently realistic.
Some new developers might be introduced to the concept initially as "tree-shaking". It's not wrong; it just differs from your preference.