Minecart with command block doesn't kill itself with r=0 with riders command block and ridden ones

/summon MinecartCommandBlock ~ ~ ~1 
{
Command:"/say start",
Passengers:[
				{id:"MinecartCommandBlock",Command:"/say 1"},
				{id:"MinecartCommandBlock",Command:"/say 2"},
				{id:"MinecartCommandBlock",Command:"/say last"},
				{id:"MinecartCommandBlock",Command:"/kill @e[type=MinecartCommandBlock,r=0]"}
				]
}