Tammy Duckworth is the last person who Tucker Carlson should be attacking. While in the past, I've agreed with some of what he has said, and think that his economic positions are much more populist (and thus, more in line with the majority of Americans) than most other Republicans, I think he's crossed a line here.
To be fair, Tammy Duckworth's criticism of Trump's speech at Mount Rushmore was flat-out dishonest. She portrayed it as Trump talking about statues of "Dead Traitors".
Trump did no such thing. There was not a single reference to a single Confederate figure in his speech. Not one. There were references to the Presidents on Mount Rushmore and a wide litany of important American historical figures of all races. Duckworth's comments were (at best) from a speech written before Trump's speech without her listening to it; at worst, they were a deliberate attempt to deceive and feed into a poisonous narrative that our President is a Neo-Confederate. (He's not, and that's silly beyond words.)
Tammy Duckworth isn't sacred; she's a politician who may well be Biden's running mate, and may be the 47th President of the United States. If it matters when Donald Trump lies, misspeaks, or deliberatly omits key facts (and he has done all of that and it does matter), does it not matter when Tammy Duckworth does the same? She's hardly a nobody, and she's way beyond Ilhan Omar in terms of importance. (Ilhan isn't gong to be Biden's running mate.) How is it out of line to call her on such a misrepresentation?
I certainly don't think that Duckworth should be above criticism. Just because she is a military veteran (and an amputee at that), does not mean that she can't be criticized for her policy views or the comments that she makes. However, what Tucker Carlson did here was to discredit her military service and challenge her patriotism, a personal attack that goes far beyond the realm of legitimate criticism. This is almost an analogue to the Gold Star family that Trump attacked back in 2016.
He was within his rights to criticize them for their political positions, but he went beyond that, and personally defamed them (i.e. saying that Khizr Khan's wife was "silent" and implying that she was under her husband's control; downplaying the military service of their son). I also see a similarity between this and Trump's birtherism attacks against Obama, which went far beyond the legitimate criticism directed by Republicans at Obamacare and other policies of his.
