The link I included is a comment from the developer that added it to Ars. Some of the later comments are fairly aggressive.
Also from the comment thread (note the job titles of the commenters):
Kurt ( Tech Director ):You guys should whitelist Ars in your ad blockers. Blocking ads makes my foster baby cry.
Clintology ( Developer / Proj. Manager ):
Please whitelist ars in your ad blockers.
We make nearly all our money by selling campaigns which are promises to deliver a set number of ad impressions. Ad blockers make it increasingly hard for us to meet those (you can imagine with a site full of technically inclined people we have a lot of ad blockers), which makes it harder for us to sell campaigns in the future.
Thus we make much less money and we have to fire our employees and friends, obviously can't pay for high-quality authors, and can't add cool features to the site, which really sucks (I presume you read Ars because you appreciate the scope and quality of our articles).
We don't run annoying ads and we don't run very many ads.
Another alternative is to purchase an Ars Subscription which removes ads and gives you lots of other cool stuff too.