"I don't take one thing back," he said Monday.
NFL spokesman Randall Liu said the league will look into it.
Raiola said fans have been particularly hard on him because he's been with the team since 2001, when it started a slide that has become the NFL's worst eight-season stretch in more than a half-century.
Raiola made the gesture Sunday during the winless Lions' 20-16 loss to Minnesota.
"I'm just tired of hearing it coming at just me," Raiola said. "It's coming at me because I've been here for years. I've been through the losing. Me, Jeff [Backus] and whoever else are the head of the losing."
The Lions (0-13) have lost 20 of their last 21 and are 31-94 since 2001, falling to the league's poorest winning percentage (.248) over an eight-season stretch since 1950.
"I'm just so frustrated," Raiola said. "I'm tired of being a doormat for people to just talk to us how they want to talk to us. I'm just not going to put up with that anymore."
Raiola wishes he could give some fans his home address.
"I'd do that, but you can't," he said. "Nobody plays with fists. Everybody wants to play with metal."
Pittsburgh Steelers linebacker James Farrior was fined $7,500 this season for making an obscene gesture toward Cleveland Browns fans. Farrior said he was upset because fans were celebrating a minor injury to a teammate.
San Francisco kicker Joe Nedney was fined $7,500 last year for making an obscene gesture toward fans at home.
In his final season, Vick was fined $10,000 by the NFL and agreed to donate another $10,000 for making an obscene gesture with both hands toward fans.