A work of fiction that exists only to promote a particular point of view is not actually fiction, but rather a polemic. Some of these have been successful and influential, from Plato to Rand, but they tend to have a different audience than fiction, and are read primarily for their ideas rather than their artistic value. Your best bet, in this case, may be to position your work primarily as a piece of philosophy. You may indeed have only limited interest from publishers and readers because of the nature of your ideas, but some make take you seriously because of the honesty of your approach.
On the other hand, if you want to make this a real, living, work of fiction, then having a character be your mouthpiece is a bad idea. People will find it preachy, and reject your book as a creepy form of propaganda. Instead, you'll need to build a book the same way anyone else does, with fully developed characters, plots and settings, and let your philosophy just be part of the background material that informs everything else. As a writer with strong viewpoints, it's nearly impossible to believe your philosophy won't find its way into your writing, even if you aren't forcing it in.
Among my favorite books are those that espouse political philosophies I don't share (The Moon is a Harsh Mistress) or center around characters whose moral choices or commitments I disagree with (Lolita, Boys of Life) or that contain controversial moral claims I find questionable or specious (Dhalgren), yet what makes them work for me is that the writer has allowed the book to live for itself. You don't have to agree with them to engage with them. On the other hand, nothing turns me off faster or harder than a book or a movie that self-righteously demands I agree with something I find immoral, or that hagriographies an immoral person as a hero to emulate. In fact, I don't like such works even when I agree with them.