First of all, I did not delete his post. It was another moderator on the team who did so. Secondly, if he had said "In my opinion, A17 seems to be a mess and probably will be delayed to 2019" there would be no problem. Instead, he posted "According to a source, A17 is "a mess" and won't release until 2019"
The first is just his opinion and readers can dismiss it or agree with it and I have no problem with that.
The second is a claim to special knowledge which presents the information he is giving as a fact. It is how false rumors get started and because I know that nobody on the internal team would characterize A17 like that, I know that it is a lie designed to create doubt and perhaps make himself seem more important.
Again, the fact is that A17 is progressing well. In my opinion, it could be released today as an experimental build. But it's not my decision and the owners want to get it more polished before releasing it even as an experimental branch. That is their right.
I am honest. When I disagree with something I post a rebuttal. It's what is happening right now in response to your post. The only things I delete are insults, libel, and spam.