Board Thread:Naruto Discussions/@comment-26773508-20150905054531/@comment-5273810-20150905081948

In universe reason, probably was an unknown or experimental area of Jinchuriki science. There is no reason to suggest that Minato even knew about that area of science. However, Killer Bee seemed to know about this when he removed a tentacle from the 8 tails which could be explained as a few or combination of different factors. First possible reason is, it was found out later on after all it was 17 years latter who knows maybe that knowledge had been found out by then. Second possible reason is only the Cloud knew it. I tend to not believe this myself as it doesn't make sense. So before I get caught up on this I'll move on to the "other" reason.

The "Real World" Reason is simply a plot hole to bring about something that had to have happened in order for the story to begin. This isn't the only plothole related to that point in the plot as both Minato and Obito were a bit off as well and logical issues happened during both combat and character interactions.

Its kinda like with Obito and Itachi. A blatant plot hole is built into their relationship. How you ask? If Obito wanted to build up the Akatsuki and get tailed beasts along with speeding up the clock on his plan, the answer would be to show Itachi to be the mole for the Leaf he really was. Then when the civil war started he could use the situation to start the 4th Great Ninja War. He could then use the Akatsuki to swoop in on certain battlefields to steal the Jinchuriki they wanted for the Gedo Statue without even attracting attention to themselves as they would be just another casualty in the war against the opposing villages.

Then once all that was done, Obito could do what he did during the 4th Great Ninja War, take a Rinnegan eye from Nagato once he stabbed him in the back and start the Infinite Tsuychiomi(or however that is spelled).

But back on topic. Killer Bee surviving in the fashion he did actually brought up a very interesting perplexing and even alarming piece of information. No Jinchuriki technically had to die and in fact a plot hole of seemingly minor significance is shown through it.

Imagine the Akatsuki go and capture Shukaku from Gaara instead of removing the entire thing(like they did) they instead remove everything but a drop of Shukaku's chakra. Since Tailed Beast chakra regenerates this doesn't change the density of the chakra they got so it doesn't matter or affect them whatsoever. In the situation I mentioned Gaara lives, they still get Shukaku, and everyone is better off, no one loses. The Akatsuki would probably even have Jinchuriki voluntarily give up their tailed beast in turn for being looked at normally by their fellow civilians.

Indeed it also brings up the fact that no jinchuriki from a village should lose their life from having their tailed beast removed because of the want for a new Jinchuriki. Indeed whole combat sciences could be used to bolster someone's natural chakra levels and give them access to new chakra natures and Tailed Beast based Kekkei Genkai.

These are some more plot holes brought about by the same contributing factor. So simple answer. Yes it was a plot hole.