I suppose I should expect it from AKR but really, the idea that a champion is somehow not all he could have been until he wins in a Ferrari is total nonsense. In practical terms, it's a world drivers' championship, and all the cars from Ferrari to Force India are basically four wheels, an engine and some wings, so it doesn't matter what you're driving.
Lets take a few examples:
Juan Manuel Fangio: did win for (Lancia-)Ferrari in 1956 but hated his time at the Scuderia and left as soon as he could. He's much more synonymous with Mercedes and Maserati and it doesn't diminish him any.
Stirling Moss: Wouldn't touch Ferrari with a bargepole, but still an absolute legend.
Jack Brabham: Can you imagine him at Ferrari? No. Does it diminish him? no.
Jim Clark: Only ever drove for Lotus (another evocative name), unquestionably an all-time great.
Jackie Stewart: Turned Ferrari down because they messed him about, and he was only ever going to say yes when Ken Tyrrell rang. Another all-time great.
Alain Prost: won three titles at McLaren, wooden spoon at Ferrari. Then they chucked him out because he dared to criticised the car, which was rubbish that season. But at
Ferrari that's blasphemy...

Ayrton Senna: Never drove for Ferrari, and it's probably just as well. Given his absolute total focus and dedication to his work, the kind of nonsense that went on at Ferrari during the 80s and early 90s (see above) would probably have ended up in him murdering someone out of sheer frustration.

Jean Alesi: turned down Williams to drive for Ferrari. Won only one race. Tragic.
Another interesting case study is that apart from Ascari, Fangio and Schumacher, Ferrari have had some pretty average world champions. Look at the names: Hawthorn, Phil Hill, Surtees, Scheckter. Even Lauda is probably the least respected of the triple world champions. It's almost as if Ferrari had a deliberate policy of hiring good-but-not-great drivers to show it was the car and not the driver that was the crucial factor, and I think that probably was the case.
And the idea that McLaren are just an average marque is laughable. Ferrari may be the most evocative name in F1, but of the teams still running McLaren is definitely second, and by some margin.
Jim Clark, Monza, one lap down...