This is an instance of "but someone else also does horrible things". That may very well be true but isn't really an argument for why the "horrible thing" we're discussing at the moment isn't horrible.
There's a great article by a journalist explaining this phenomenon (my google-fu is weak today). He discusses how every time he reports on "X country has done atrocity Y" he gets replies of "but why aren't you covering country Z which is also horrible?".
If the standard for being able to protest anything is that you must do full due-diligence and protest all similar things then no one would ever be able to protest anything.
There's a great article by a journalist explaining this phenomenon (my google-fu is weak today). He discusses how every time he reports on "X country has done atrocity Y" he gets replies of "but why aren't you covering country Z which is also horrible?".
If the standard for being able to protest anything is that you must do full due-diligence and protest all similar things then no one would ever be able to protest anything.