Why does politically incorrect writing need a special place of publication?
Many works of art criticize the current state of affairs. Political change, subversion, or social analysis are the motivation behind many works of art.
Currently in the West we have a dominant feminist ideology. Writing something not feminist, or anti-feminist, appears politically incorrect. But half a century ago, the dominant ideology was what feminists call "patriarchal", and feminist writing was politically incorrect. So where was it published? Wherever it would get the most exposure.
Mainstream publishers avoided feminist writing at first, so feminists created their own publishing houses, their own printed magazines, and as their thoughts gained acceptance, they were slowly picked up by mainstream presses. Today, feminist writing is often no longer discernible as such, because it has become the common thing.
So if you have a political agenda, the first thing you will want to attempt is getting into mainstream publishing. You want to be read, and to reach the widest possible audience you will want to get published by a publisher that has the power to get your book into book stores and reviewed by the major news papers and tv shows.
If getting into mainstream publishing does not work, you will need a network of like-minded people and create your own outlet. If you want to change the world, as feminism did, you cannot manage that alone, so your second step must be to find or create a community of people who want to fight alongside you. What that community's outlet will be, will depend on the message you want to send and the target audience. It could be a blog, a YouTube channel, a newspaper, a print-publishing house, or anything else – but most likely it will be all of the above. You (and your community) will need to be your own marketing managers and think about how you can reach your readers and make your writing sell. Again, think of feminism fifty years ago and how they spread their ideas. There's lots of books that summarize their strategies, and you can learn a lot from them.
Your question, then, shouldn't be where you can publish politically incorrect writing. If it is good writing, and not too offensive, it will get published by regular publishers. If it is too offensive, your question needs to be, where you can find a community of like-minded people that supports each other in publishing their works. If it is bad writing, then you need to learn to write and should stop thinking about publishing anyway.