It's never been a condemned action to go into a mall. But, then again, you didn't just go to a mall. You did so while covering your face and refusing to abide by recognized security measures.
Regardless of your justification for doing so, that is going to be taken, by many people, as either a very foolish or ignorant action based upon social norms. And the fact that you cite it as a form of mourning doesn't help when many see it as a time of withdrawal from society rather than an opportunity for a shopping trip.
While your actions and intentions might be exactly what you say, all we have to go by is your word. And, on the internet, that doesn't count for much. Some people are going to believe you; some people will not.