Millman competed at the Atlanta Open where he caught COVID testing positive recently and he took to Twitter to explain what he thought about the whole situation. While being vaccinated and entering the US without trouble, Millman saw that nobody really paid attention to the recommendations and guidelines in the US. Therefore he questioned why such a strong stance is being taken on Djokovic:
"I’m out with covid. I was just in the states and it didn’t really feel like too many were following any recommendations or guidelines there. Which is fine, but therefore I can’t see then why @DjokerNole can’t come and compete."
He followed it up with:
"Let me be clear. If everyone in the country was following guidelines then I’m all for them enforcing a vax entry policy. But from what I saw pretty much no one was, the tournament allows non vax citizens to play and only 30% have had a booster.”
While Millman points out rightfully that Djokovic isn't really a threat, the problem is that allowing Djokovic to enter would essentially give him preferential treatment for something that millions of others have complied with including most of his colleagues. Djokovic is free to choose what he puts into his body and the US is free to choose what kind of laws it applies on its territory.