Slaughter House-Five chapter 4 "Why me?"

Billy kidnapped by Tralfmadorians? "Why me?" People are always asking why me when something bad happens to them but they don't realize life is not perfect or fair. What Billy says is a very ignorant question in my opinion because everybody has passed through rough times in which everything seems to go wrong. Maybe Billy thinks his life is very bad, but he doesn't realize that there is a lot of suffering and pain all over the world. The book takes an unexpected turn. I thought this book would be only like a recount of war from somebody who hated it. It apparently goes around Billy and war was just a very important part of his life but there are more stories that take place in the book not only war.I wasn't expecting this, why aliens?? This really makes me think that Billy is crazy, I don't know if he is a reliable character and if everything he says really happened. Maybe the war made him crazy and he is in a mental institution. Some people that lived a cruel war like Billy end up in mental institutions because all they saw in war never stops haunting them. I think the writer is trying to take away a little seriousness from the book including aliens in it. He may be trying to include some humor to the book. He started the book, and I thought it would be another book of  wwII but now with this I don't know what will happen. 

Human's free will? When Billy is kidnapped by the Tralfmadorians they talk about the earthlings, they say we think we have the freedom to choose what will happen to us and what we will or will not do. I think it is wrong to say this. To some extent we may choose some aspects of our lives but something just happen, they are unexpected and you just cant choose whether they happen or not. This events are just a part of life and destiny.