Supposedly, this shows that you can’t trust Daily Caller. There is only one problem. The article on Daily Caller doesn’t say “all Democrats”. It doesn’t even imply that.
To quote the article’s first paragraph: “However, she has avoided helping some Senate Democrats because she’s mad at them for failing to show adequate support for her deeply unpopular attempt to change people’s diets.” This is about a law passed by the Federal Senate in 2010. Wendy Davis was a senator at the time, but in the Texas State Senate. So the article does not apply to her, and showing that Michelle Obama tries to help Wendy Davis is only debunking a strawman.