Forever Unsolved

BIG spoilers ahead, if you don't want to know how the last story of Poirot ends or if you don't wish to have the series ruined for you, don't read the rest.

I'm so pissed because this plot makes zero sense. Poirot, king of telling people that there is never a good enough justification for murder, actually reveals himself to be one of the killers in this book. I cannot believe this. I'm so frustrated. Oh, of course, and then he dies.

The other murderer is actually not a murderer at all, he just... says a bunch of words and that's apparently enough to manipulate people he just met into killing other people, uh. Where's the accountability??

And then what?? Are we supposed to think he was just good enough to manipulate Poirot into killing him or that Poirot really just decided, on his own, to kill the so called "murderer"?? When he could have just stopped him from the beginning instead of letting it all escalate???

Nah, not buying this.

Have been reading Poirot for years, he's one of my comfort characters and this was severely out of character. I cannot accept what was done to him.