Earlier quoted context omitted.
If they bought the stock they are helping fund the business. The shareholders are keeping the stock because it represents their stake but the actual money paid can be used by the company selling its stock and that’s the primary purpose. Whether the buyer/investor votes, or knows what they bought, doesn’t change anything in that respect.
If you buy into an IPO you're helping the business raise funds. If you buy stock from other stock owners it doesn't help the business.
Additionally the people who own shares own the company so what benefits the shareholders benefits the company and vice versa as their interests are the same.