But the thing is... it says "Heather's Heavenly Vapes" on it...
The photos are attached to comments made by the user (a forum post), something the author may not want to have associated with their work - and they have every right to defend it's use. Damages don't have to be monetary.
A note saying you claim no ownership does NOT excuse you from the law, and would have ZERO effect in court.
If it's on the internet, it's not personal use.
If it says HHV on it, fingers will be pointed at them. Even if a fan created it and supplied the links, it'd be up to HHV to defend themselves.
The things you said are mostly true, it's just that none of it applies to this situation... not even a little bit. The lines of distinction can be thin, but they matter greatly.
The author is dead. WB purchased the rights to this when they started making movies. JRR Tolkien (the author) has no feelings on the use of the name, images, etc. I conceded that the poster could be notified by WB, and even given a cease and desist letter. That does not change the fact that WB would not pursue the matter if an individual poster did this. Here is why.
Of course they would have legal right to try to stop you. But to what end? They could pursue a hundred of these, and if the people receiving cease and desist letters change the avatars, and there is no consideration gained by the poster, what will WB pursue it for? It would cause them great expense for minimal (if any) gain. The fact that there is no monetary damage makes the pursuit of the case against a poster on ECF a loser for WB. In my book, that is as relevant as it gets. I would say, therefore, that it applies to this situation.
There is no legal precedent to hold HHV liable for an unassociated third parties actions. There is no case law I am aware of to back your assertion to the contrary. Sure, a judge could create this precedent if he felt like it, but that is extremely unlikely, since there is a high likelihood of it being overturned on appeal. Corporations generally do not make a case of extremely unlikely payoffs with low end pay outs.
The cease and desist to HHV had teeth because there were merits to the arguments that HHV enjoyed value added to their product
through the use of this name. Therefore, there was consideration. It became a worthwhile matter to pursue for WB. Wisely, HHV immediately and publicly complied with the cease and desist letter. Without a violation of the cease and desist letter after it's receipt (I have no idea of the specific language of it) it will be difficult for WB to pursue this matter successfully.