It was their right to fire him for anything they want, they did not need to give any reason and what ever they say it is is more than they are required to do, welcome to reality. Awwwww
When public figures and other radio and TV personalities sign a contract and are getting paid by ESPN, then they agree not to make racist or other types of statements that could reflect negatively on ESPN. Comparing Muslims to nazis is not a smart thing for any public figure to do. All Americans are free to say what they want and ESPN is free to hire and fire as it sees fit. The fact that he quickly deleted the tweet shows that even in his own judgment he knew it was a mistake.
Schilling has a history of saying stupid (*)(*)(*)(*). But he seems OK with ESPN's handling of it. Why should I care?
MOD EDIT - Rule 3. If he was unjustly treated by ESPN he could sue. Evidently he believes he has no cause to sue.