Marion Carl (who knew a thing or two about air-to-air combat and aeroplanes) is on record somewhere as having said that given an Fury with an afterburning engine, he'd have happily have taken on any aircraft anyone chose to point in his direction, and would have been willing to have a crack without the burner...; he still thought the FJ-3/4 perhaps the finest naval aircraft he ever flew.
The point JN challenged was:
"No non-STOVL land-based design has EVER been developed into a successful carrier-based variant."
It doesn't matter about massive redesign for carrier use (which is a form of 'development', even if pushing the word to its very extreme); landing speeds; over-engineering, or anything else raised to attack JN. Also, note the assertion's use of the emphasised 'ever'. JN's rebuttal of that absolute was not imprecise. A post-facto application of historical conditions to undermine JN's point is rather unfair.
Had JN attacked a point phrased - 'only with rare exceptions has a land-based design been developed into a successful carrier-based variant and the chances of this being done today given the cost, increased structural stresses of carrier operations and current approaches to aircraft design where the over-engineering of the past doesn't take place', then 'savaging' the post would be reasonable.
He didn't. The generalised charge made about turning a land-based design into a successful carrier-based variant is inaccurate, whether or not one thinks JN is using the point to push the case for a navalised Typhoon. Trying to savage him for attacking an inaccurate generalisation is, if I may be so bold, unfair.
There is a useful and valid debate to be had about whether a Seaphoon could ever provide the sort of capability the RN requires at a reasonable cost and without serious redesign. I'm in the same camp as N_a_b and GK, i.e. unconvinced: but I don't think it's valid to imply that JN's rejoinder is little more than pro-Typhoon propaganda, since he actually has a point regarding the intial observation.