Evan Johnson, a rising senior at Cornell University who grew up in Sag Harbor and worked as a desk attendant at SoulCycle two summers ago, got out of her mother’s car and asked if she could share her perspective on a SoulCycle investor’s role in a Trump fund-raiser. “I’m very upset,” she said. “I feel like it goes against everything they tell people to work toward and all the values they say they promote. I think Mr. Ross should consider his constituency and the base which supports his business.”

Mr. Ross, the man whose political fund-raising is at the center of this tempest, is a billionaire who owns the Miami Dolphins and has a wide range of business interests anchored by the Related Companies, one of the most powerful real-estate interests in New York. (Related Companies retains a majority stake in Equinox, of which SoulCycle is a subsidiary — the holding is divided among the firm’s partners, of which Mr. Ross is only one, making him a minority investor.)

Mr. Ross issued a statement on Wednesday noting that he had known President Trump for 40 years. He said he agreed with him on some issues, but “strongly disagreed” on others. He also said he has always “been an active participant in the democratic process.”

Mr. Ross has primarily been a donor to Republicans, though he has given to Democrats as well over the years, including Senators Robert Menendez of New Jersey and Mark Warner of Virginia, as well as Representative Lois Frankel of Florida.

So far in 2019, Mr. Ross has contributed $150,000, topped by $50,000 to the Republican National Committee and $33,600 to the National Republican Senatorial Committee. In the 2018 midterms, Mr. Ross’s largest contributions were $155,000 to the political committees of then-Speaker Paul Ryan and $150,000 to the R.N.C.

For one anonymous SoulCycler, though, Mr. Ross’s political contributions weren’t the only problem. The rider took issue with how the fitness companies responded to the uproar by trying to diminish Mr. Ross’s influence.