"The jellyfish should have handed government over to a member of the party who wanted brexit."
I'm sure you're aware of it but a PM is usually the leader of the largest party in the HoC. A departing PM can't just nominate his successor in either role. So when Cameron decided to quit the only option was for the Conservative party to go through its normal procedure to choose a successor who, by convention, HMQ would invite to form a government.
The members of the party who were most strident about wanting Brexit contrived to either quit the contest or stab one another in the back. The result was someone who many of us suspect of having been a crypto-leaver who wanted to protect her position in the event of the expected referendum result.
The leading Bresiteers have only themselves to blame for one of them not being at least a candidate for PM.