An arguement that is often made against the continued depiction of Joker and Harley's relationship is that by doing so, DC is implicitly condoning abusive relationships.

The same arguement is also made on the subject of whether Joker should show affection and tenderness towards Harley at any time.

This is ridiculous, and a fallacy.

All it reflects is an incredible double-standard which exists within society and the hyper-sensitive, ultra-conservative attitudes our culture has towards sex and non hetero-normative, unconservative relationships.

For this arguement to hold any weight, one must also consider the amount of violence, murder and criminal activity that takes place within television shows, movies and comic books. While there is a faction of society that argue these themes and elements prove influential, most people become hyper-defensive of their right to access violent, bloody and gory depictions within various forms of entertainment.
When it is these issues on the line, people are quick to cry censorship and fascism, just as quick to vocalise their frustration that anyone would consider them so immature as to be unable to tell the difference between fiction and fact, fantasy and reality.

People use the claim that abusive relationships happen in real life. Well, so does much of the other unsavoury content we see depicted. Often these movies, books, TV shows and comics feature intense, unsettling and disturbing violence against women and children. The plots of lauded and celebrated comics such as Sin City and From Hell pivot around horrific violence against women. But no one is claiming such depictions should be eliminated from comics - indeed, people instead claim reflection of reality is important!
Rape, drug use, murder and other criminal activity play critical roles. This is very true of comic books and very true of the Batman world where murder, death and violence is portrayed as a normalised aspect of Gotham City. In fact, we 'expect' such things from Gotham City.

Indeed, in being Batman fans, we laud a man who uses brutality and violence to carry out a personal vendetta of vigilantism. True, Batman never kills and never forces himself on anyone, but he is quite happy to use extreme force - and even takes pleasure in doing so.

And while Batman never kills, we are often expected to laugh along with the Joker as he does what he does when he kills people or commits crimes. He is written in such a way that he comes across as witty, charming and funny.  

And yet no one has tried to claim that Batman or Joker fans condone vigilantism or murder.

It is pure hypocrisy to laugh or cheer Batman and Joker on on one hand - to acknowledge and understand fully that what we're reading and viewing is fiction, fantasy and has no place in the real world - and then on the other to become hyper-sensitive about a depiction of an abusive relationship and claim that people will 'get the wrong idea' or feel abusive relationships are 'okay'.
It is ignorant and disingenuous to broadly generalise that people are not astute and intelligent enough to tell the difference between fantasy and reality.

A depiction is not the same as approval or condoning. By the same token, any form of entertainment which portrays any form of violence and criminal activity is also condoning that activity. A huge proportion of such entertainment does not have neat, resolved conclusions, justice is not always reached for the victims and the guilty are not always punished.  Why do we expect more from the Joker and Harley relationship when we are so content to be complacent when it comes to rape and murder?

A depiction is just that: A DEPICTION. It would be dishonest and false to both characters to depict them in any way other than what they are, and that is completely insane and screwed up. As such - so is their relationship. The abuse is not glorified or celebrated. It is a fact borne of their fractured psyches. And as discussed elsewhere on this website, it is not the only element involved in their relationship, which takes place on far deeper and more subtle levels as well, ones that involve consensual D/s and sadomasochism.
By being true to that and depicting it honestly, the intelligent reader is actually able to recognise for themselves it is an unhealthy and undesirable relationship whilst at the same time understanding these are works of FICTION and that they can therefore continue to enjoy the relationship the same way they enjoy all the murder, violence and crime that occurs throughout the rest of the Batuniverse.

Why is it understood - assumed even - that readers know it's not okay to dress up like a flying rodent and break the bones of a few punks - and yet, when it comes to this relationship all of a sudden everyone's attitudes turn paternalistic and infantalising? If we are mature and sensible enough to be critical of what we read or watch to the point we don't try and replicate it in reality, why is it assumed we lose that ability when it comes to this relationship?

I feel what is at work here on a far deeper and more subconscious level is a certain type of misogyny. I truly feel that part of the outrage by those who casually view this relationship is due to the fact Harley is such a likeable character and so easy to identify with. She's sweet, has an edge of innocence and naivity to her, and loves passionately. There is a lot of commonality between Harley and the average person and as such no one wants to see her 'hurt'.
But if Harley were a more unlikeable character, I somehow doubt there would be such a backlash against JokerxHarley. Indeed, I think there would be an undercurrent attitude of 'she deserves it'.  There often is, against unlikeable female characters in bad situations - an attitude that is also implied by the creators of the material as well.

But maybe I'm just a cynic.

At any rate, while, yes, this relationship is abusive, it is not only that and the arguement the abuse alone is enough to see its demise is highly flawed and extremely hypocritical.  If you are someone who has a kneejerk reaction to this relationship, I do entreat you to stop and consider what it is you're really reacting against and if the courage of your convictions extends beyond this issue.