It's a historically understood metaphor. Like "Uncle Tom," it gets applied pejoratively, like to someone perceived as thinking themselves better than others. Unfortunately, that for some can be anyone who rises through independence rather than dependence.
Which is my point here, that he'll probably be attacked for daring to suggest people should (here comes another one) leave the Democratic plantation.
If you don't like it, it can be disregarded, but I think it makes a useful point.
