Seems like nonsense to me. If you are running Windows, which most people are, you are almost certainly going to have Word / Wordpad etc.
A far better solution to .doc attachments is to ask if your content really needs to be in an attachment. A lot of the time it simply doesn't.
To be honest though this isn't really a problem is it? When Microsoft first brought out their .docx format it seemed like there was a lag before other free applications could read the files. I found that a problem.
Today, everyone has an application to open a .doc file. A lot of people are using gmail. I just click the preview button. I assume that Windows Live Mail has something like this which makes use of Office365 functionality (might be wrong on this). It really is a non-issue.