The other side of this is: is it possible to have known, and do nothing, but still be partially justified because of the fear of the fallout of your revealing it? Like, in Smith's case, he would actually stand to lose a lot if he turned on his boss (and had nothing but Hollywood rumors to back up his statements). Should we assume that just because some people who *might* know something aren't talking because of spurious reasons? Like, they are somehow just okay with Harvey Weinstein being a serial sexual abuser?
One of the reasons this story needed to be revealed the way it was is because all of these other people who knew were inside the very system where these abusers literally run the show. It's something to consider. Also, we must not forget that Harvey may be a big one, but there has to be more where that comes from. These people are going to be even more careful in protecting themselves now.
More on topic: I think this is the right response from Kevin. Nobody can peer into his mind and extract what he knew, or what his situation was if he did know, but this is the response you want to see. Anything which creates more visibility to the issue, and doesn't hamper the progress with regards to showing that the industry should not support these people in high places is what you want to see.