I think it is healthy that there are some contrary views to those of the manufacturer. After all, if Air Power Australia has a bias, Lockheed Martin has a substantial bias too. It would help if the contrarians base their conclusions on sound data, but if that were the case then their debunking of the capability would be very bad news indeed.
It is sometimes healthy to try to shine a light on dark places, if only to keep those with the biggest vested interest (more) honest. If LM has nothing to fear then no doubt data substantiating that is in the hands of the decision makers who can make balanced judgements. Of course, they can always validly claim the need for confidentiality, which is a perennial difficulty when it comes to public accountability on military projects.
As far as America is concerned, the F35 projects looks firmly in the 'too big to fail' category and they will force it through. Given its record to date, it has given its detractors plenty of circumstantial ammunition with which to attack it even if they lack the heavy ordnance to deliver a knock-out punch. I am not unhappy that someone is asking awkward questions. There is a distinct whiff of bluster and fudge about this programme that gives the ignorant (of which there are many, including me) an uneasy feeling about how the government is spending our money.
I want to be wrong. I hope it eventually turns out a world-beater in its class, and that the UK then buys lots, and UK jobs are sustained by sales around the globe. If it were my decision though, I would wait until I was much, much more certain that it was going to be the bees knees before signing the contract.