I believe they are tacky and shady in explicitly soliciting for adult content providers, but bear in mind that pretty much everybody is happy to host it, unless we're talking about illegal content. You'll have a field day if you traceroute any of the major porn sites. Or, to take everybody's darling, AWS, consider [1]. My bet is that pretty much everybody is glad to do business with adult content providers; they are just quiet about it...

[1] https://forums.aws.amazon.com/message.jspa?messageID=44204#4...