Smooth, were the million other threads not good enough to post this question that you started another one?
Here is an answer I wrote a while back for pretty much the same question. I hope that answers part of your question.
The issue of apostasy & its punishment is very interesting as far as the Islamic history is concerned and it is best debated in the context of Musailma. The wars fought by Hazrat Abu Bakar (ra) are commonly known as “Wars of Apostasy” which gives the impression that wars were about the claim of prophet hood by these people. But was apostasy & its punishment the sole reason Hazrat Abu Bakar (ra) & other Sahabas fought those wars? Or was the reason different but ‘false claims to prophet hood’ one of the common traits of these people? For that you have to read history a little more in depth, certainly not the ones they teach as the course books in Pakistan. 
All history is biased, regardless of who writes it, especially the opinion on justification, morality and reasons of going to war, as people’s lives are at stake. Is the War on terror, a war against violent religious extremism or is it against Islam? Is the war with Iraq about WMD, security and a cruel dictator or about Oil and Israel etc? The opinion varies and is usually dictated by one’s own perception and biasness towards the issue. Not only the victors write the history but most often than not it’s rewritten in the following years as needed & the dominant view among the historians of the victorious becomes the commonly known history, regardless of the fact that it might not have any truth to it.
The whole saga with Musailma is particularly important as it gives many different clues that weakens if not totally reject the reasoning commonly known, for the strong stand of Hazrat Abu Bakar :ra:. Here are a few things to consider:
#1. Contrary to common belief, Musilma’s claim to prophet hood didn’t come after AnHazoor (saw) death. Instead in the life of the Holy Prophet (saw) he made several attempts to be recognized by him as a fellow prophet & was hopeful that afterwards the position of the ‘head of the state’ of the newly founded Muslim State will be given to him. He wrote letters to the Holy Prophet (saw) addressing himself as a prophet & also addressing AnHazoor (saw) as a prophet. So, the question arises, if it’s necessary to go after a false claimant and punish him, and if that was the reason why Hazrat Abu Bakar (ra) went after Musailma then why AnHazoor (saw) didn’t? And if AnHazoor (saw) didn’t go to war, how can his perfect follower, Hazrat Abu Bakar :ra: , who wouldn’t even budge an iota away from his sunnah would go to war?
#2. The claim of Musialma changed after the demise of AnHazoor (saw). He shifted from claiming to be a fellow prophet to a better prophet and also claimed that Hazrat Abu Bakar (ra), who was already elected as Khalifa (Head of the Muslim State) at that time, should follow him. He refused to pay dues, such as Zaka’at and also changed the law of the land by making drinking lawful along with Zana etc. Not recognizing the head of state, in this case denying bait of a (rightfully guided) Khalifa is considered ‘rebellion’ and throughout Islamic history it has caused the followers of both parties pull out arms against each other. Refusal to pay the state dues, make amendments to the law of the land is another unprecedented crime. Not to mention massing army & making alliances with other favored groups against the ‘head of the state’ and create a law & order situation is considered ‘treason’ and even the great democracies of today consider it a crime punishable by death. And Musailma did all the above!
#3. The history also shows that there were other claimants of ‘prophet hood’ at that time that were mostly brought to justice but there were some that were left alone. One has to investigate why they were forgiven? One of the wives of Musailma (if I remember correctly her name was Sajjah) also claimed to be a prophetess. Though when she couldn’t get along with Musailma (who in the opinion of most historians was only using her) moved to her homeland Iraq, which at that time was not part of the Islamic state. There is no evidence that Hazrat Abu Bakar (ra) or other went after her to punish her or her believers, for her false claim to prophet hood.
Most Muslims who appose the idea of ‘waging a war against the apostates’ argue through Qur’an stating the fact that it preaches no compulsion in religion and gives freedom of belief to others. IMO, the close study of the case of Musailma gives a far better argument, as Qur’an is open to interpretation, and mostly the pro-death-penalty for false prophets give Hazrat Abu Bakar (ra) incident as their sole argument, with the case of Musailma as the center piece.
who fought against them and defeated all of those 20+ false prophets in Arabia. Remember Abubakar, Ali, Umar, Talha, Saa’d bin Abi Waqas, Jafar Tayyar and many other top Sahaba