It's not hard, it's an innate characteristic of porn. It's the inverse of rule 36 - as long as a communication channel exists, it will be used for porn, no matter how inconvenient it might be. Also, playing it straight, someone will have a fetish for porn over that channel, no way around it.
Because no one would ever want to see porn during sex with their partner without being obvious about the whole thing? (depending on relationship and stuff, naturally)
It's not hard, it's an innate characteristic of porn. It's the inverse of rule 36 - as long as a communication channel exists, it will be used for porn, no matter how inconvenient it might be. Also, playing it straight, someone will have a fetish for porn over that channel, no way around it.