Honestly, I can speculate on a sympathetic side to Akiko's actions. I mean, look at it from the perspective of someone who really cares for the people under her. She knows witch fights are deadly dangerous, and that a lack of Seeds can kill you (let's assume she doesn't know about the witchbomb for a sec). You have a few girls in your charge, so what's the best way to make sure they a) don't die, and b) stay topped up on cleanses? It's pretty simple if you narrow your focus down to protecting just a few people, really. You set up a system where other girls you don't care about take the risks fighting witches and deliver you Seeds. That means that you hardly ever need to risk yourself or your girls in witch fights, just the occasional show of force to stop an uppity meguca from saying 'nah, I'm not paying you for the privilege of existing here'. Rin's healing gig came later and added on a new way for her to gain Seeds without fighting, meaning that she could upkeep more meguca for longer in the case of a witch drought.
If she does know about the witchbomb, then the urgency to make sure she has as big a stockpile as possible just gets even worse. She then knows that in the case of a gem darkening, she would have to hunt down and kill one of the people she's protecting in addition to the pain of losing a friend. Would also be the reason why she's careful about who she lets into her group, as anyone she brings in needs to either be able to supply Seeds or have some sort of hax to intimidate others to give her Seeds.
Sadly, we actually have context for the line of thought, too. Narrowing your focus down to saving or protecting less people is what Homura did, really. She initially wanted to save all her friends, but at the end the only person she really cared about was Madoka. And we're not blaming Homura for, say, threatening to kill a spiraling Sayaka, or taking Charlotte's Seed after not really trying that hard to save Mami. It happened, but the context and intent was important.
It doesn't help the people that get the short end of the stick, but if she does really care about Rin as a person and not a resource (Sakura certainly does, and Akiko was sort of holding her back for Rin's sake I think) then her preparations to get her back at all costs make perfect sense. I mean, would Homura stop to negotiate with someone who took Madoka hostage? There would be stopped time, and then there would be all the bullets forever.
Maybe this is just my optimism and general faith in humanity showing. I'd like to believe that Akiko, for all her faults, is still human. I have no idea if any of this is correct, but it at least is a try to understand her reasoning. Someone else can come up with the cartoonishly evil version.