(Denny Crane: "Sometimes you can only look for answers from God and failing that... and Fox News".)
Are we describing a concept of states' right being inviolate and a viable doctrine only when its application coincides with one's own ideological perspective of a situation or in an outcome with which that person (or identifiable group) finds contrary to what they want the outcome to be?
Either constitutional law is a continum and has a high degree of predicability, or it is merely a bundle of suggestions. Most of the time the law is consistent with justice, that is a happy circumstance. But when justice and the law are not congruent, and it's a case in which equity cannot be a remedy, the law's consistency, predictability, stability and precedent are superior to the anecdotal case before a court.
We select trial and appellate judges to--as is the phrase so popular among talk-show folks and those who either don't understand the role of the judiciary or want the court to decide only the way they favor - - decide cases based on the plain language. Yet, when courts exercise their role in interpreting ambiguous and vague constitutional commands (like due process, equal protection, etc.), there is always the same discrete group that screams for judges' scalps. Courts are "out of control" when they apply long standing constitutional principles to evolving real-life circumstances and when they protect minorities from the tyranny of a transient majority. It's a political reality as old as the Constitution itself and neither the screams of today's right fringe nor the future discontent of tomorrow's agitated interest group will change the sanctity of the judicial process and the role of judges.
Who knows what you may have read but ignorance of the constitution is rampant. Of course a state constitutional amendment can be challenged. You think NY could pass a law making slavery legal again?
So Yes you are mistaken and Yes it can be appealed to USSC and likely will be.
You most certainly were mistaken. A state constitution can be modified to grant to its citizens rights that are not granted to them under the US Constitution, but it cannot be modified to take away rights that are guaranteed to them under the US Constitution. The US Constitution sets a floor, but not a ceiling, to the rights that a state can bestow upon its citizens.
You are probably thinking of a related issue. If a state supreme court premises its logic on the state constitution alone, without reference to the US Constitution, then the decision of the state court is binding and cannot be reviewed by the US Supreme Court. However, this is subject to the above qualification. For example, if a state constitution is interpreted by a state supreme court to grant to the citizens of that state a right to privacy that includes the right to abortion on demand, and the state supreme court does not invoke US Constitutional analysis, then that decision cannot be reviewed by the US Supreme Court. However, if a state constitution is amended in such a way as to deprive citizens of that state the rights that they are guaranteed by the US Constitution, then the state constitutional amendment can be challenged in federal court, as happened in this case. The federal judge found that Section 29 of the Nebraska Constitution violated the First and Fourteenth Amendment rights of gay Nebraskans, and (impeccably correctly) enjoined the state from enforcing the amendment.