Why the hell does that even matter? I'll ask you again, are the countries which kill people not allowed to mourn their own dead? Especially when this isn't anything like just a bombing through bad intel, this is delibrately attacking civilians for no purpose other than to end human life. The US might have had some bad incidents in war, but so has everyone, including the whole list of people you rattled off before.

So what is the problem with the US mourning it's dead?