He aimed both barrels at New Zealand rugby, star player Sonny Bill Williams, and claimed there was a strong anti-All Black feeling among the Samoan team.
"They cannot disregard my opinion because I am right there, standing in front of the bullet, on the field facing the six foot six [Schalk] Burger. They think the Samoan rugby players team are dumb so they continue to treat us like shit."
He also said the IRB deliberately set out to disadvantage Samoa by giving them shorter scheduling between games.
But Fuimaono-Sapolu said his tweets were a way of bringing attention to more serious issues.
"I don't know why such a big deal is made out of them, especially when it's actually the truth. It is powerful, but people have got to relax a bit, and not take it all at face value."
Fuimaono-Sapolu, a lawyer, shunned the party lifestyle as a young man in favour of helping educate his nephews and nieces.
He said: "You never know the makings of a man on the field. Our job is just to distract the masses. The real heroes are in the community, the underpaid nurses, the teachers.
"In the end we have got to be a bit deeper than the vanity of Sonny Bill Williams."
The 30-year-old second five claimed the Samoan team, the darlings of many Kiwi rugby fans, dislike the All Blacks and many want to see a Northern Hemisphere team win the World Cup.
"Many players say 'stuff them, they don't do anything for us'."
Fuimaono-Sapolu, who plays for English team Gloucester, said he would return to Samoa tomorrow to "face the music".
"I am going to sit on the seawall [in Apia] and open myself to any abuse - or hugs. The love and hate, I will sit there and take it all."
He has set up a sports academy for Samoan sports players, and said the ultimate dream was to give his country's youth opportunities inside Samoa.
"I just wish the IRB would include us."
His mother Luni Sapolu, also a lawyer, said her son's mouth had been getting him into trouble since he was a kid.
