The sherman antitrust act of 1890 was passed primarily because of: the practices of various trusts in the railroad, steel, tobacco, and oil industries. the popularity and political influence of john d. rockefeller. multiple examples of false and misleading advertising. the monopoly abuses committed by alcoa.

The practices of various trusts in the railroad, steel, tobacco, and oil industries.

"Antitrust Act" should tell you that it's against "trusts" which monopolized various areas of business and commerce.  A primary culprit was the Standard Oil Trust, which had been formed in 1882 and controlled over 90% of oil refining capacity in the United States.  John D. Rockefeller was the founder of the Standard Oil Company, but the Sherman Antitrust Act was not about his personal popularity.

There also would be antitrust action against ALCOA (Aluminum Company of America), but that action occurred in 1945, after the Roosevelt administration accused ALCOA of violating the Sherman Antitrust Act.  What became the ALCOA corporation had just begun its history (in 1888) at the time of the Sherman Antitrust Act and hadn't yet developed into the full "Aluminum Company of America" until 1907.