I can't understand such statements, and it bothers me - not the statements themselves, but rather the seeming necessity of them. Why do people assume that I might be promoting living like a junkie if I write a story about one?
I won't go into why people assume "gay propaganda" or such things - this is nothing but stupid. What I can't put my mind off is the idea that you promote everything you write about. It can't be ideas of the character - for some reason, they must be yours, even if they fit perfectly into the ideas of the world you're telling about. If a videogame allows you to shoot someone, it's being branded as "propaganda of violence"; if a cartoon portrays someone shooting someone else, the same brand is applied soon after its air time.
At the same times, the stories of classics are often prone to display darker sides of humanity - greed, murder, lust, disdain and so on. Those are the same stories I've never heard being referred to as any sort of propaganda. In fact, I've barely ever seen them being referred to as anything other than the highest class of literature or cinema. It might be because I wasn't looking hard enough, but the point remains: there's a certain level of double standards when it comes to art.
What's the deal here? Why do old stories get some slack cut while those closer to contemporary are being so thoroughly branded?
In a similar vein, Dan Carlin talks about this in regards to "great" historical figures in his podcast Harcdore History - Wrath of the Khans. Basically he says that we tend to look past the actual personal motivations of the perpetrator of an event (or creator of a piece of art) if enough time has passed for there to be a significant cultural shift. His initial example is Alexander the Great, who waged war and killed a shitload of people, but ended up spreading Hellenism which lead to artwork that we enjoy today. People today would say that it was worth the sacrifice of those lives and credit Alexander with doing this great thing, but ignore the idea that it wasn't his actual intention to spread a great artistic and cultural movement.
To apply the idea to your question, people tend to view things more closely that they have (or believe they have) a more intimate understanding of. Since these issues are at the forefront of modern day culture, people are more apt to apply their personal beliefs and biases to a piece, whereas art created hundreds or thousands of years ago can be viewed without that filter.
TL;DR: People see what they want to see.