From the article: The addendum also expressly bars the companies from “engaging in any practice” that would exclude their Free File offerings “from an organic internet search.” Note the term "organic" which suggests the page "naturally" ranks in the first few hits. The agreement doesn't seem to prevent Intuit and others from both buying ads to populate the top of search results and SEO'ing the crap out of it to make…
I agree with your argument in the general case, but in this case that seems like what they would want: not to exclude the possibility of advertising or SEO for the other products, but to rule out doing reverse SEO (or just robots.txt to exclude it from search engines) on the Free File pages.