I don't think comments by Vincent are known to Japanese fans or Kinoshita. I keep hearing that he's said or posted bad things but I don't know what they are and there's no added language barrier for me. Regardless, he seems quite popular in Japan. What I find a bit much is that he specifically mentions receiving support towards his participation in the Beijing Olympics. He's been set up as a direct rival to Japan's own skaters and already has the bonus of US score inflation in addition to any financial support.
Some of the arguments I've seen in favour of the sponsorship from Japanese fans on Twitter are:
Yuzu receives support from P&G, a foreign company (though they're a multinational corporation and he receives support from the Japanese branch and promotes products available exclusively on the Japanese market)
UNIQLO supports international sports stars and this is no different (UNIQLO has stores around the world and promotes a global image)
Javi was kind to a certain young world bronze medallist who was also his rival so we should all support Zhou's sponsorship (though Yuzu received no funding from any Spanish companies to push him towards an Olympic medal)
Of course there are many people asking Kinoshita to support Japanese junior skaters in particular but another group who seem to be sad and ashamed that anyone would leave anything but supportive comments under the official announcement Tweet.