This is to be expected and unless MS see huge uptake in these areas I have no doubt some investors will continue to grumble. Investors don't like high margin business' expanding into low margin areas generally - which is what MS is doing here. They love it when a low margin business expands into high margin - for example when grocers like Tesco start selling lots of clothing at far higher margins than tins of beans - but going from high to low means that your average margin for the business could go down and by default that tends to trigger concerns for certain investors.
I guess they might be mollified if MS gave better guidance on the longer term importance of their efforts here - right now, if I was a neutral investor I'd see them playing second fiddle by a long shot to Apple and Nintendo with no guarantee of victory. Or maybe the investor's in question haven't reviewed MS strategy deeply enough themselves. Could be either way or both.
I doubt MS will pull out, personally, they've put in a lot of money/effort and are finally getting somewhere, but this a very expected view from the investor community. And in the end, overall they're profitable and can afford what they've spent on entertainment products such as Zune and Xbox.
Try to be reasonable... its easier than you think...