First of all…
Speilburg is a hack.  So all of this counter-soap-boxing is even more trivial.  But, I’m going to defend the decision.  Though I doubt Speilburg made it entirely on his own.
In fact, the fact that he is a hack, helps.  Since, I’m sure that “terrorist” line really has no secondary meaning to some subplot involving existential bereavement or something.  Nor do I think he’d be able to make it all that funny anyway.  If we were talking a master of black comedy like Todd Solondz, yes, I’d be upset.
But Speilburg is a panderer and manipulator of emotions, and not a good one at that.  In fact, just yesterday I was talking to a professor who was complaining on how ideologically exclusive his movies are.  I.e. if you don’t agree with his values, with what he thinks is “heart warming” or whatever, you’ll be taken “out of” the movie.  e.g. you don’t think ET is cute, then you ain’t going to give a fuck, cause he just assumes you think he’s cute…  A better example, Shindler’s List, that whole “this ring could have been one more jew saved” monologue thing was so hammy, but he just thinks we all agree the holocaust is bad, so we’ll go along with it, regardless of how ridiculously melodramatic it is.
But I’m digressing.