I'm positive Mark can fight his own corner without my butting in, but for me, the line about being above reproach was uncomfortable reading. And I am that guy you portray in your point 2, and I for one felt no insult whatsoever. Clearly none was intended in the first place.
This is fiction, and fiction set in that period to boot, involving a young, privileged and wealthy individual in major cities and in high society situations of the time. In context it seems realistic that the character may have dabbled had he been there, and a stretch to infer he has an addiction at this stage. And I don't see the link between what has been written and any attempt to glorify or promote that behaviour.
According to Wikipedia (so it must be true ☺️) here in the UK we are 93rd in the per-capita alcohol consumption list against Denmark's 122nd. Half of our per-capita probably comes from the huge pub at the end of my road. But Mark's stories didn't influence our relative rankings, nor anyone to drink or take drugs, and almost certainly didn't cause some idiot to nick a road cone and leave it in my front garden.