If you are cool downloading illegally you can get it at anime-sharing.com
Otherwise, i'm pretty sure you can buy legally on the parade website and amazon.jp.>>195841
Pretty sure there is a lot of fundashi out on the wild. Since this is a more female oriented board you probably won't find as many here. But for example in 4chan's /y/ threads there is a lot of male posters, in reddit's /r/yaoi (i think it's called) too.>>195857
The same that it is for a woman, i guess? I don't really see the difference.
Most people enjoy cute/deep stories, good characters, pretty art and cheesy love stuff, which yaoi/bl has tons of. Yaoi also tends to have more story (be it good or bad) as opposed to hentai/yuri, which tends to be mostly pure smut and fanservice, which could attract all kinds of people and sexes.
I personally find it absolutely normal when straight (or otherwise) men enjoy bl/yaoi.