I agree. It could be confused with a commodity content site. This is very much not "Hacker News!!" It runs the risk of raising the noise level.
I like introducing people to this site.
Why? Do you prefer for HN to be a place where only TechCrunch, NYT and Mashable get submitted? Such a button would greatly improve the variety of submissions here.
Any user that recognizes de HN button knows how to submit to HN anyway. Too much visibility of the site has lead to connectivity problems. And surely it's no good to HN become a clone of reddit, digg, delicious or whatever. HN is better being a different taste of internet.