They're a court. Their job is to answer the question asked, not some different question they might think is a better one to ask. As Opoponax points out, what's an acceptable level of agency fees probably wasn't part of either side's argument.
It wasn't, neither was it a fact mentioned, referenced, suggested, or relied upon by the Court in the majority opinion. This has been told to him before, numerous times.
Did the majority explain how they managed to find spending money in dues to help provide a stable basis for the Union to perform its primary task is unacceptable compelled speech, but being forced into the collective bargaining is acceptable compelled speech?
The facts of the case involved collective bargaining, and it was during the process of collective bargaining that the compelled speech transpired.
The Governor, on one side, and public-sector unions, on the other, disagree sharply about what to do about these problems. The State claims that its employment-related debt is “‘squeezing core programs in education, public safety, and human services, in addition to limiting [the State’s] ability to pay [its] bills.’” Securities Act of 1933 Release No. 9389, 105 S. E. C. Docket 3381 (2013). It therefore “told the Union that it would attempt to address th[e financial] crisis, at least in part, through collective bargaining.” Board Decision 12–13. And “the State’s desire for savings” in fact “dr[o]ve [its] bargaining” positions on matters such as health-insurance benefits and holiday, overtime, and promotion policies. Id., at 13; Illinois Dept. of Central Management Servs. v. AFSCME, Council 31, No. S–CB–16–17 etc., 33 PERI ¶67 (ILRB Dec.13, 2016) (ALJ Decision), pp. 26–28, 63–66, 224. But when the State offered cost-saving proposals on these issues, the Union countered with very different suggestions. Among other things, it advocated wage and taxincreases, cutting spending “to Wall Street financial institutions,” and reforms to Illinois’ pension and tax systems(such as closing “corporate tax loopholes,” “[e]xpanding thebase of the state sales tax,” and “allowing an income tax that is adjusted in accordance with ability to pay”). Id., at 27–28. To suggest that speech on such matters is not of great public concern—or that it is not directed at the“public square,” post, at 16 (KAGAN, J., dissenting)—is to deny reality.
In addition to affecting how public money is spent,union speech in collective bargaining addresses many other important matters. As the examples offered by respondents’ own amici show, unions express views on awide range of subjects—education, child welfare, healthcare, and minority rights, to name a few. See, e.g., Brief for American Federation of Teachers as Amicus Curiae 15–27; Brief for Child Protective Service Workers et al. as Amici Curiae 5–13; Brief for Human Rights Campaign et al. as Amici Curiae 10–17; Brief for National Women’s Law Center et al. as Amici Curiae 14–30. What unions have to say on these matters in the context of collective bargaining is of great public importance.