The prevalence of ad-hominem attacks against Icaza is unfortunate. You can agree or not with his more-pragmatic-than-some stance towards open source software, Microsoft, etc., but the fact remains that the guy is a first-rate builder and hacker.
There have been a seemingly endless stream of incidences of him shilling for MS, going on for several years now. The two most common themes of shilling are trying to push Mono as a viable linux technology, trying to push Mono as a dependancy on common linux systems, and shilling for OOXML like you see here.
Another (slightly less common) theme is his ad hominem attacks on [F]OSS figures/organizations/supporters such as the FSF and Groklaw, like you see here.
He's been at this for years, it's no stretch of an imagination to call it a "long history".