Paul McBride QC, who has represented Celtic manager Neil Lennon in front of the SFA, also claimed the governing body was now "the laughing stock of world football".
McBride told BBC Scotland: "Officially tonight we now know the SFA to be the laughing stock of world football. The decisions are incoherent, they are, on the face of it, thoroughly dishonest. I never thought they were biased or prejudiced but now, hearing what they've done today, it's very hard to escape that conclusion."
He added: "We have a position whereby the person who was provoked gets a four-match ban and the person who does the provoking is let off.
"We have a Rangers player, Bougherra, manhandling a referee, not once but twice, and there is no ban.
"We have El-Hadji Diouf who is abusing the Celtic manager and throwing his top into the crowd and refusing to leave the park and behaving badly - no ban.
"What does any sensible person think of that?"
McBride, whose studying of the SFA regulations ensured Lennon's recent touchline ban ended earlier than the governing body had envisaged, added: "Celtic, and I hope they refuse to comment on this, I suspect will be privately bemused and seething by today's result.
"I was prepared, as were Celtic, to give them the benefit of the doubt with their various incoherent and inconsistent decisions. I don't think they're getting the benefit of the doubt now from anyone.
"I don't think this benefits Rangers either - this makes our governing body look beyond stupid."
Source: PA
Source: PA