The search algorithm goes way out of its way to determine some measure of "legitimacy." Obviously this is a vague and hard-to-define measure, but the goal is commendable: show results that are both relevant to the user according to Google's relevance metrics and legitimate according to who links to it, quality of the page, freshness, etc. Whatever qualms you might have about the vagaries of the search algorithm, you can't dispute that it's difficult to game.
Meanwhile ads are chosen by what brings the most long term value to Google. Gaming this system is much easier, and usually begins with paying more per click. This favors advertisers with higher margins, which is harmless for innocuous queries like "flowers" which make up the bulk of search ads. For bail bonds, however, this favors advertisers with higher margins, which in turn rewards exploitative providers over the legitimate bail bondsmen this author seems to think will be harmed. If anything, this is actually a boon to the more socially-minded bail bondsmen this article is concerned about: exploitative bail bonds businesses that go out of their way to saddle their customers with debt will not appear on the top of the page, raising more legitimate ones.
Another point: one of the consequences of being able to pay for ranking is you can place ads on terms that are not really related to your business. For instance, "Home Depot" queries tend to show ads for Lowes and other competitors. In a similar way, searching for "bail bond counseling" and other terms tends to include at least one for-profit bail bond operation that offers no or nominal counseling. Meanwhile if there are no ads, then the legitimate counseling services will float to the top of the page. Likewise for queries for all the other services this article claims will be hurt.
Source/disclaimer: These are my personal opinions as someone who works in ads at Google, (but was not involved in this decision). All my points come from publicly available info. Please don't mistake this for anything but my own views.