"I would like the honor to be the first to point out that Microsoft 'and' inclusivity doesn't seem to extend to XP users with IE9," said someone identified as "Parrotlover77" on Monday. "As long as XP exists, my websites can never not support IE 'quirks' which basically means HTML5 and much other new Web goodness is not a practical business decision."
Others echoed that.
"The day you ship a decent browser for the most-used operating system in the 'enterprise' world (Windows XP) you may obtain the right to criticize other browser vendors," said "VirtualBlackFox."
Microsoft has taken heat for its decision to offer IE9 only to customers running Vista or Windows 7, not the still-dominant XP. Last year, analysts called the non-support for XP a "major shortcoming" of Microsoft's strategy and predicted it would slow uptake of IE9.
Windows XP's last browser is IE8, which Microsoft launched in March 2009.
When asked to sync Hachamovitch's claim of inclusivity with its decision to dump Windows XP from the IE9 support list, a Microsoft spokeswoman forwarded a statement that the company has used repeatedly when asked about its IE9 ruling.
"Windows XP users have a fast, safe, reliable and private browser in Internet Explorer 8," the statement read. "Internet Explorer 9 requires the modern graphics and security underpinnings that have come since 2001, and is intended to be run on a modern operating system in order to build on the latest hardware and operating system innovations."
In the past, Microsoft has dismissed calls for supporting IE9 in Windows XP as a non-starter that would have meant developing to the "lowest common denominator."
Mozilla has been especially vocal about Microsoft's verdict, claiming that if it could manage to make Firefox 4 and its successors work on XP, Microsoft should have been able to do the same for IE9.
Microsoft will maintain IE8 through the end of Windows XP's support lifespan, which expires in April 2014.
According to Forrester Research, IE is used by 59% of corporate computers, while Firefox's share is approximately 18%. IE7 accounts for the biggest chunk of IE usage -- well over half -- Forrester said in a recently-published report.