Muslim extremists routinely fire their heavy weapons from populated areas. Look up some of the Palestinian photos and the Iraq war photos.
If civilians died, be assured the jihadis were trying to get return fire on them.
And by using “protected” sites to conduct combat ops, they removed the protective status and the target can be hit. . all in accordance with the Law of Armed Conflict.
Oh, and how do you KNOW they were civilians? The don’t wear a uniform, they don’t have any standards of dress, weapons or behavior, and by the time the “investigators” arrive (anti-American UN-types), all weapons will be gone.