You can reduce the amount you comment to, but is it really not good for wh sites? I have used this quite a lot and received no complaints to my host. And I may be wrong but I don't think google will punish you as its all off-site.
I'm 99% sure this script is fine for white hat sites. I've been using it on mine for months and my google ranking has only got better.
Google can't punish you for it because its off-site
How does the format of the comments come off? Does it just leave whatever you put in the comment field and then drop the link in a signature or something?