Your quote doesn't even make sense here since they're not suppressing his COVID ideas. Regardless, the scientific community considered it and responded: https://www.johnsnowmemo.com/
While I'd agree that he took some controversial and unpopular positions, I don't think it's accurate to say: "the scientific community considered it and responded". The John Snow Memo was not a specific reply to Levitt's ideas, and I am not sure what the 'scientific community' is. That memo had a relatively small number of signers, so claiming that they represent any large and diverse community is a bit hyperbolic.