Assuming this is referring to 6/2's puzzle (which there are spoilers for below)
I do sort of agree, but "means" has its own meaning beyond the plural of "mean". It's common to say "a means to an end" - it's clearly a singular word of its own. There are other words on the answer list like this too, where you figure it's plural and can't be the answer until you think, "well, maybe that word has enough of a meaning in its own to not just be a plural?"
I could go either way with this, honestly. It's a bit confusing but I don't think it's in any way wrong to leave them in.