It is ok to express outrage over one thing even if there is something more outrageous happenning. Don't express outrage over Hillary's emails because there is larger corruption, or don't express outrage over an Iran deal because Isis exists.
What happenned to Cecil was awful. It doesn't mean that terrorism is ok. If anything, the conclusion to make is that celebreties take on these causes because there might be a debate about it. No one thinks Al Queida is cool, but plenty think abortion is murder, and that trophy lion hunting is fun!
The issue is when you start to make moral equivalencies, or call people animals for being upset that a guy paid $50,000 to have a beloved lion captured, imobilized, shot with an arrow, and be allowed to suffer for hours and hours until it was finally shot and skinned.