How does this chapter serve primarily as sinclair's muckraking chapter?

Muckrackers are journalists who try to expose corruption and scandals that the government officials have. However, since they want to earn more and sell more numbers of papers, they often present both truthful things and allegations as something spectacular and scandalous. In his chapter 9, Sinclair used many muckracking techniques even though some of the statements were questionable to their truthfulness.

Yes it has . that is why fake news is such an issue