"Serious virologists" isn't proof.
Which virologists think it's natural, and which think it's unnatural?
Now lets see the data and thorough reasoning by each, and see the rebuttals of each for their opposition's reasoning, etc.
Until this is laid out clearly it's all shallow discussion - that no one should blindly trust or believe.
The above is the scientific process, method.
There clearly isn't consensus yet.
Literally no one, including the authors of this paper, contends the sequence is "unatural".
unatural + n == correctly spelled unnatural
unatural - u == correctly spelled natural
How the hell are you supposed to guess as if the context of viral sequencing is somehow easy to parse correctly?
You realize that their saying "natural" or "unnatural" completely changes what they're saying to the polar opposite, right?
So now clarity is pedantic?
Seriously?
If HN had subreddits there'd be one similar to /r/WatchRedditDie