As far as I can tell, DHS are the ones not properly managing risks here, not the mom traveling to Disney.
I think the implication that he or she was trying to make is that statistically, those on the coasts travel by air more frequently. As someone with a mom who was very afraid of flying and terror related risks thereto, I know that fear largely dissipated when I finally got her to fly a few times. It's not an allegation of ignorance but that of relative inexperience (was my take, anyway).
The frequency argument is an interesting one. This recent survey seems to indicate that travel maps pretty closely (within a percent or three) to population of the area which I wasn't actually expecting (sure, lobbying group doing the research caveat caveat): http://airlines.org/wp-content/uploads/2016/04/2016Survey.pd...
It also looks like there's a pretty significant difference between Midwest and Plains states in terms of numbers - less people, many fewer airports.
I totally get why the stereotype kinda makes sense given a certain view of a large swath of the country (though I've generally found these to be poor guides) but the statement would've worked without the regional or gender modifier :)
This is also a bit raw for me because I JUST flew my kids to Disney haha