He asked an opinion and he gave it. He wasn’t “lying”. The likelihood of contracting and spreading is severely diminished if vaccinated. Not to mention the likelihood of hospitalization. The data still backs that up. Fauci is going to err on the side of caution ergo his OPINION on unvaccinated people joining for the holidays. We only saw a small clip but he could have very well been more concerned about the unvaxxed person contracting it from an asymptotic vaxxed person and potentially sending them to the hospital.
Personally my whole family is vaccinated and I wouldn’t be overly concerned about a single unvaxxed person in my house. I may still question their judgment but ultimately my sympathy for anyone not willing to take the precautions available to them is pretty much used up.