Have you seen how poorly non-Microsoft browsers are supported by Microsoft's web tools?
Exchange is a pain. Hotmail, on its last (last I saw - no longer use it) big change took months (many) for the Firefox version to arrive at a comparable feature set as the IE version. If you are not running Windows, you will face an even worse browser compatibility. For a long time, any ASP.NET application built with the GUI tools on Visual Studio was pretty much guaranteed not to work properly on anything but IE.
No. I don't think the reaction of the call center worker is surprising in any measure. He could know non-Microsoft browsers were not supported and inferred the thing being from Google meant it would not be compatible.
BTW, would it be compatible with Firefox on Linux?