It does sound like it was an ill-advised joke by President Obama. I am one that believes that Donald John Trump is truthful about his never touching alcohol, much less illicit drugs. I still find it odd that he would sell Trump brand wine and vodka after the sad demise of his elder brother, Fred.
Speaking of jokes, I guess the OP is also outraged over the jokes that Donald John Trump, Junior, made about the Aurora movie theater murders, etc.
Trump Jr. joked about Aurora shooting, Arab stereotypes, overweight people in shock-jock interviews - Oct. 17, 2016
One tidbit:
"The Trump son also noted there were hours of footage of the "The Apprentice" left on the cutting room floor that would appeal to those with a "sick sense of humor."