Excellent write up by Vanity Fair.
It being engineered as a bioweapon is in the realm of a crackpot theory, but it being just a poorly contained natural research project was fairly reasonable. Some prominent people mixed the two up on purpose and eventually the whole thing - both ideas - got labeled a crackpot theory by people who just saw some headlines.
I guess I don't quite follow with how people would think that it being a weapon that spread intentionally or unintentionally is the base case.