Some charity might be employed before judging a person. Is this asking Carson qua future president, or Carson qua a doctor?
It would be well within the purview of a doctor to advise behavior he believes to be wise. That does not mean he wishes the government upon you to enforce it if you refuse.
If Carson wants to carry water for the Brady Campaign then that’s up to him. But my right to have an AR-15 is not up to him. And I won’t put him in a position where he can interfere with my right.
It’s not like we don’t have plenty of other talented people who know what the 2nd Amendment means.