People had been accusing Cosby as early as the 80s about assaults that happened as early as the 60s. Similar to how UK comedians joked openly about Walliams being a creep long before the allegations ever became public, the allegations against Cosby became public after the comedian Hannibal Buress joked about it on stage. It's not a 1 to 1 comparison by any means, but there are a lot of parallels in how the situations are playing out.