Is the Huffington Post... sexist?

If pointing out that a woman isn't acting "like a lady" -- a standard of respectable behavior for women -- is sexist, then why isn't this HuffPo headline also considered sexist?

Since when did dividing the sexes by "ladies" and "gentlemen" -- holding individuals to high esteem for proper, civilized behavior --  become a sexist notion?

Just as West's comments toward Wasserman Schultz were meant to chastise her inappropriate behavior on the floor of the House of Representatives, HuffPo's headline is clearly meant to convince readers that President Obama and Speaker Boehner are acting irresponsibly -- i.e., not like a man.  Either that, or the Huffington Post is incredibly sexist.