Look at his role as Director of NIH.  He controls the government grant money related to immunology.  In addition he's on Bill Gates board of directors (likely more including Zuckerberg, Soros et al).    If you piss off Fauci, what's the likelihood you will get a grant from Bill Gates (who has the largest non-profit in the world)?  That would be a big fat Zero.  https://www.niaid.nih.gov/about/director