Warren’s statement seems to be designed, and timed, for political effect, and is consistent with his prior statement advocating gun control.
LSD, for example, is a dangerous drug with no beneficial use, whereas a pistol can be used for self-defense and training. Even “prohibited persons” (an ever-expanding list that includes certain misdemeanor convictions, certain people in divorce proceedings, people who renounce citizenship, non-immigrants, dishonorable discharge, medical marijuana users, etc.) may rightly want to defend themselves. Blaming the gun dealer here is really low, and opportunistic.