"The rationale in both cases was that the standards are tougher and will require more time and effort to teach and learn."
So... let me get this straight. They need more resources to hold general education children to a higher standard than previously. They do not have resources to accelerate some children and bring others to task. So, they have to reduce acceleration.
This is a problem of a tax base that is lazy and under-funded, NOT a problem of minimum standards.
By blaming Common Core, you might as well suggest that we eliminate public education period, so that we can reach high achievers. After all, the high achievers NEED education, whereas the plebes can just go on trailing the plebes of the rest of the OECD, so we can have Algebra in 5th grade for 2%. There's sustainable public policy for you, not alienating the majority of your tax base at all! (Not.)
The problem is NOT standards.
It is a lack of resources coming from a low tax base which comes from low salaries, hoarding, and a myriad of other issues.
But let's suppose someone is willing to defend to the death their child's right to receive a personalized education, at the expense of 30 other children receiving a decent education. This is America, after all, and such a thing would not shock me in the least.
Even so, if Common Core is raising the district standards by a year, then keeping the gifted program at the same place will by definition reduce the advancement by one year. The other kids are catching up. Your kid isn't falling behind. They are being asked to do more. This is good, because your little genius will have more talent to work with when he tries to start a company here. He won't have to deal with visa applications for 15 Finns or something.