I'd disagree from a rudimentary understanding of the situation and the law, which i openly admit may not be 100 percent spoton.
However, the NLRB denied players' rights to unionize, as such, they are not afforded protections for performing lawful strikes. The legislature is not attempting to prevent their ability to execute the right of free speech. However, it is stating plainly that it won't allow the school and/or local economies to be held hostage either. The players can be discharged or replaced.
Further, even if they were a recognized group of workers. The Missouri players strike would be an unlawful strike under Section 8(b)(4) of the national labor relations act as it attempts to compel the employer to change an activity that had not directly affected the Athletic organization to which they belonged. They'd have a hard time riding the student and the athlete sides to extend activities affecting student affairs to their athletic organization as well, which by itself had not been discriminatory or otherwise given cause for unfair labor or economic strikes that would be lawful.
The problem that i have with the legislation is that the state shouldn't have a say in athletic scholarships as it is my understanding that the state contributes no money to the scholarship.
That said, if a player strikes for the most altruistic reasons unrelated to his specific athletic dept conditions, he should do so understanding the risk is permanent replacement or discharge. No one should deny his right, but the player must determine if the cause supercedes the risk.