It is rude of Felipe Massa, but yes, I would agree with him on this.
Let's see:
Lewis Hamilton
Kimi Räikkönen
Fernando Alonso
Jenson Button
Hmmm, which one of those has had a mediocre career in F1 up until just very recently? Yup, Jenson Button. He also seemed weak in the second half of the season. And even though he was insisting he is not, it looked like he was cracking under pressure, and he sounded desperate many times during the season.
It's great he won it, congratulations to Jenson, you completely deserve it. But if we compare him to the other 3 mentioned, he is the weakest one.
And I have to say that I don't think the hit in the head has caused Felipe to give out such statements. Perhaps some of you people have not been paying attention, but I think he has done that for years in F1. He IS a little man compensating for his small size and feeling of insecurity by being egotistical and outspoken against others. That's him. Like it or not, that's him

I've gotten used to it and expect to hear more of it - as we know many said after he had woken up after the accident that he is still the same person, so yes, more of this is expected. Keep it up, Felipe! You are a funny little man