It wasn't libel the last time you brought it up and it isn't libel this time. Soon failed to disclose non-trivial amounts of funding that he received from parties who have a vested interest in deriding climate science. Given how often his work has failed to pass muster when scrutinized by climate scientists and skeptics, it is hard to fathom how any of this can amount tosimple incompetence.
The article you linked to is almost comical in its petty malevolence, well beyond the point of self-satire. This kind of character assassination, however reprehensible, is ultimately irrelevant. If you believe Dr. Wei Hock Soon is wrong, then show where and how he is mistaken.
Climate scientists have been doing that for almost 25 years at this point, and Soon's response has pretty much been to complain that he's being bullied and that science is being politicised. I find that to be actually comical, almost as much as the presumption that an intelligent and intellectually honest person could do this for as long as Soon has. And that his association with political and industrial think tanks is a non-sequitur in this regard.