You're not going to be able to make sense of things if you just blindly assume that everyone who joins ISIS, acts on behalf of ISIS or in some other way associates with ISIS takes everything as literally as you're describing. Like in any organization, but certainly the radical terrorist kind, people subscribe to the propaganda or ideology or mission statement or whatever to different degrees, some may fall for it hook line and sinker while others don't buy it in the least but just run with it because it's convenient.

What is 'unable to go to Syria'? Let's be serious, if random fourteen year old girls can make it from Western Europe to Syria, then adults like those who committed this attack, the one in Nice, etc. can do the same, if they want to bad enough. They don't want to; they are interested in lashing out against their society and making the headlines, not in burying themselves in Raqqa. And I very much doubt they care too much whether al-Baghdadi lives or dies, except that him dying would provide another excuse for an attack.