The way I heard it is that Ron Paul puts out his less government, more freedom message, free of copyright, and let's anyone reprint it. He has no control over whether Carto or anyone else publishes it. He just wants the message to get out.
Are you absolutely sure Ron Paul "writes for" Carto's publication? Or is that from something you read here posted by a Paul hater?
Okay, try the link below. They're supporters of his on their website. Does that mean he wants their support? I don't know. Has he rejected it? I don't think so. And perhaps this is all coincidental. But if it quacks like a duck, it's a duck.
http://www.americanfreepress.net/html/paul_banned.html