Sorry I don't follow. Could please elaborate. You mean bots do query 'cialis' to get an ad-sense ad, while they are the same guys benefiting from ads shown? Or what? I genuinely want to understand the problem and most importantly the motivation.
I don't understand the motivation either, but I think what they are attempting is to make e.g. typing cialis into Google suggest specific queries like the one i showed, which may be so overspecified they provide the spammers' links.