I'm a straight guy who is a fan of some yaoi couples (Note the avatar of Wally and D;ck from DC Comics). I don't read the genre just to read the genre. I just read manga's or FF if they interest me. Basically, I'm a fan of couples who just make sense to me, whether they be yaoi, yuri (Note the sig of Azula/Ty Lee from Avatar), or straight. For example, I'm a major fan of Kimimaro x Jugo in Naruto, a major fan of Azula x Ty Lee from Avatar, and a fan of Death the Kid x Liz in Soul Eater. Those are yaoi, yuri, and straight. I really don't like using those labels though. I honestly just call them all just couples or pairings I like because that what they are.
So, am I a fan of reading it? Only if I like the pairing, fanfiction wise. I don't read yuri or yaoi just to read it. I just sinply don't try to look for it because I like reading stories for stories that appeal to me and if they come up to read, I'll read them. Basically, I read FF on established manga's/comics/etc...on couples I like, whatever genre they be.
Favorite pairings? Wally/D;ck, Kimimaro/Jugo, and Captain America/Ironman, although I like Steve (CA) with Peggy more, although she died and well, things go on. Not many, but I seriously love the first two I named.
Can a straight person like it? Yeah.
Why do I like it? I'm an open minded guy and if two characters make sense to me to be paired up, then they just are in my head.
Closing notes, I'm really open minded with the fandom of anything. Some pairings I'll dislike because I don't like them matched up, but that's not based on sexual orientation. I'm chill if people like different couples involving the same character than I do. Example, I love Justin/Medusa, I don't mind/I like Justin/Giriko, and I'm okay/don't care with say, Justin/Marie or whatever.
Hope all that made sense.
PS: Good answer SasunaruFan13 (Sasunaru, basically the most canon couple in Naruto, besides Asuma and Kurenau xd)