If Islam is willing to accept new converts, then people who leave them, because they lost faith in the religion, or change their minds, then they should be to leave freely, without dire consequences. Unfortunately Muslims are unwilling to let these apostates to leave freely, so Islam is more of prison for these people.
Muslims living in Western countries, can leave their faith with less problem (unless their family are fanatical, misguided honour and homicidal) then countries in the Middle East and Southeast Asia, where they face real of assault or death, if not arrest and execution because of strict adhere to the Sharia Law.
So do Islam tolerate apostates?
Depends on where you live, and I certainly wouldn't announce the apostasy if I was living in any of Middle Eastern countries.
Heck, you can even get arrested for possessing a bible in some countries, so who said that Islam tolerate other religions.