No reason except that, unless your blog is aimed at the early adopter crowd, people would go "chrome what?" and go away.
Yes, it can be painful, but the minimal level of such coaxing that has occurred has been helping -- IE's marketshare is shrinking ever smaller and currently stands in a place that people would have thought impossible just a few years ago.
We can make a difference if we try. We just have to be willing to act boldly wherever we can. Personally, it is my opinion that every developer should find the investment in eradicating IE extremely worthwhile even if it costs him some sales or pageviews. The masses have proven that they will switch if something they want to do asks them to do so, so let's get it started. It is really silly that we don't do this already.