The reason is that if you have a less widely accepted opinion and someone states it and you can add additional info to it which makes it "stronger" you are likely to do so.
Which still doesn't mean I believe it. As far as I know the scientific majority believe is that the virus doesn't show any indication of potential human manipulation and is very unlikely to be human made assuming China isn't years ahead wrt. virus manipulation (which doesn't mean it doesn't escaped from a lab, btw.).
But as I'm not to much involved in this I would need hours to collect sources and trace them back to their original source to provide any useful links. So no credibility to this post.