One can fault the Common Core for not including enough discrete math -- it really focuses on numbers, algebra, and eventually modeling with polynomial and trigonometric functions -- and one can fault America for putting people into the classroom who don't know math [1] and then telling them they'll be awarded tenure or not based on student performance on some test [2].
People are confusing the same old problems we've always had (poor teacher training, stupid cobbled-together curricula like Integrated Math mandates by school boards, teaching to tests with high stakes for teachers and little value for students, etc) with Common Core. Read the standards [3], folks, and decide based on what they actually say what you might actually think.
[1] http://www.nsf.gov/statistics/seind12/c1/c1s3.htm , http://www.math.vcu.edu/g1/journal/Journal7/Part%20I/Sterlin...
[2] http://education.ohio.gov/Topics/Teaching/Educator-Evaluatio...
(Evaluating teachers using student test scores has been a push of the Bill & Melinda Gates Foundation, but it's not well-supported by evidence. One more link: http://www.latimes.com/opinion/editorials/la-ed-teacher-eval... )
But what does Common Core have to do with graph theory not being taught in elementary school? It never has been, and not because of new standards. It's not taught because too many teachers don't know it, and because too many "administrators, test writers, and standards-compliance checkers" have their noses where they shouldn't! It is terrible that in the US we have this attitude that teachers must be told exactly what to teach and when. We have it because we don't trust teachers, and swapping out NCTM standards for Common Core standards doesn't change that.
Either you argue that graph theory is more important than the other topics (which?) or you acknowledge that graph theory is an enrichment topic for some students who learn the core material faster or devote more time to math study.
It is true that Common Core lacks "enrichment" -- by defining a minimum standard, it doesn't specify what to do with student with more capacity to learn. But that's left to individual students, teachers, and schools, not incompatible.
If a teacher can teach their students 7G math standards in 6 months of the year, the teacher has plenty of class time for other topics.
I certainly don't think that basic graph theory should be reserved for "advanced students." This second grade experiment shows that it's accessible to everyone.
It is true that standardized tests would put pressure to ignore this sort of "enrichment" material, but that's a (Pearson) test problem and a (unfairly constrainted) teacher problem, not a Common Core problem.
Put another way:
If a student is exceeding the test standards, there is time to branch out to enrichment topics.
If a student is not passing the basic arithmetic standards of the standardized tests, it's open for debate how to reach a passing level, or if it is appropriate to engage in a major alternative curriculum.
I think the problem is that in a vast majority of schools the classes are taught to the lowest common denominator. Sure, one , or two, or ten students could be exceeding the standards but if one or two other students are not passing the standards, I think teachers are very unlikely to introduce these enrichment topics.