If you survived a shooting tragedy, you might have an expertise in shock or in suffering, but gun control? That’s a bit presumptuous since being part of a shooting tragedy does not make you a gun policy expert. Nor does it give you the authority to dismiss the opinions of people who haven't been in a shooting.
Interestingly enough, there are survivors of the Marjory Stoneman Douglas school shooting who are pro gun, yet no one grants them extra validity. Gee, I wonder why? Could it be because the left grants validity only to the victims that they agree with?