That's not just here though. If they were to turn Roman heel and Roman successfully played into it, the crowd would start cheering him.
Vince and/or Trips understand that and understand that a character like that isn't what they want.
At the end of the day, the crowd just wants someone to "play along with them" and react aggressively to guys who feel too entitled to.
Eventually though, they get bored by guys that play along with them because they like them too much to boo their character, and they feel too cool to cheer for them as a babyface (leave that to the kids).....thus, you get an Orton or a Triple H or a Dean Ambrose or a Seth Rollins.
Roman's purgatory is better than Seth & Dean's purgatory and they've actually "played along", character-wise.