I'm of a different mindset; in that seeing different interpretations or ideas or narrative flows created aren't nessecarily indicative of a dissatisfaction with the canon. For example, in Avatar - I'm incredibly happy with the canon as presented in Katara's context; a strong dark-skinned heroine who is not presented as the trophy girlfriend of various heroes. She's a protagonist and a person in and of herself. That being said, I do enjoy Zutara fandom in that I believe they would make an interesting and fun couple. However, this doesn't mean I want this to happen in canon, nor am I unhappy with the canon presented. That being said, sometimes they are. And that's legit as well.
Anyway, before I derail into 'Katara is awesome and this is why', the conclusion that both of us came to was essentially that fans are inherently unhappy with themselves - the characters one identifies with are not only who we see ourselves as, but who we could become. They show us our potential. But the depection of characters who are involved in so called 'alternate lifestyles' or practices is exceptionally narrow, and when presented is often demonized (made fun of in the text, made a joke of, etc.).
It's why I can't really bring myself to be angry with anyone who is a fan and inserts Mary Sues or the like into their own personal fan-canon, because these kids are looking for love, acceptance, and most of all - for the rest of the world to let them know that it's alright to be who they are. It's alright to be into anthro, it's alright to be gay, it's alright to be this way. There's an extreme politique of shame, emotional killing and inferiority complex control going on in the world.
This is also why it's dangerous to introduce depections of types of characters in a narrow way - I'm looking at you, majority of BL comics & Yaoi as understood in a Western cultural context. In a very real way, Yaoi & BL have allowed thousands of young gay men to find depections of men involving in homosexual erotic acts, and more importantly to have those men involved in homosexual erotic acts not be demonized by the text. Yaoi supports the positive existence of gay sex, and offers many young men (specifically, men; BL and Women's identity politics are another issue) and outlet that lets them begin to understand that there is nothing wrong with them for being sexually attracted to other men.
However, Yaoi has a huge array of terrible tropes it re-enforces - Japan's borderline xenophobia and racism, Japan's acute homophobia (while more common, you rarely have characters who identify as homosexual; when they do they are often protrayed as the Okama stereotype (think typical 'Queen' archetype in Western media)), Japan's terribly oppresive fat-phobia, it's able-ism, and it's extremely patriarchal institutional, interpersonal and cultural mysoginy & gender roles. Some manga-ka certainly play against a few types (I read a great one about an older man in a wheelchair) but usually in a very, very safe way (said older man was rendered in a way that didn't accentuate his age, plus he was ripped and an Oyaji-type).
Where was I going with this? Oh, yeah. Identity politics. At any rate, young gay men here (in the Western world) who read Yaoi will recieve the message that it's alright to have gay sex - but the only way you'll really find someone who loves you is if you're a stick, a jerk, coded completley as a diminutive patriarchly-feminine person, willing to be raped.... The tropes go on. The enforcing goes on.
Today, listening to the new Soul'D Out album, one of the songs had rapper Diggy Mo say (in his very typically coded African-American-In-Japan-Manly voice) said in a specific way (in English, which he can speak) 'Hey boy wanna be with me datta my love is just men's memory'. I'm now hesitating to search the lyrics - alright, that's a lie, they aren't transliterated yet - because I don't want this to be a line that was intended to be presented as though Diggy was reiterating a message from a women, coded in her submissiveness and feminity. I want this to be, and I want to believe this was intended as, a message that positivly expresses romantic love between men. I feel this way because positive depections of love between men are so rare, that I have to grasp a maybe and never let it go.
In my chldhood, I'd always identified with women who were emotionally aware and emtoionally considerate and dedicated to teaching others the way of emotional understanding - but who were also strong because of this belief. I've always identified with women who were like this because, initially, I've never found a male character who embodies that kind of self-love who are strong but still emotionally aware. I still haven't. I have never seen a West-Indian character in anything. Period. I've seen a few Carribean characters here and there; stereotypical Jamaican's (the one that standouts in my mind is the strong Jamacian female activist lawyer who was a character in Boy Meets Boy).
What's my big rambling point? Basically, that the variation of characters as presented - Japanese or Western media concerned - is still exceptionally narrow in terms of what it supports positively and what it will kick to the ground as wrong. So if fans want to slash characters, make them anthro, or do whatnot with them in their fanon - I can't bring myself to be mad at them. They're victims in this, more than anything.
And don't even get me started on the representation on female homoerotic texts. Good goddess.