"Justice delayed is justice denied," said South Florida SPCA president Jeanette Jordan.
"We have waited long enough for justice for our horses."
She said people like Cordero and Cabrera are entitled to justice, "but victims deserve justice, too, and we have been denied too long as horses in our community continue to be butchered".
"Our beloved horses cannot speak for themselves," Jordan said.
"Don't let another horse owner open a stall door only to find carnage instead of their beloved pet. Don't let another horse owner find the remains of their missing horse tied to a palm tree and butchered. Don't let another innocent child be haunted by the sight of the remains of a dismembered, eviscerated horse.
"All these things and more have happened in Miami-Dade and Broward Counties. It is an unthinkable, unimaginable and unacceptable continuing horror."
At least 22 horses were slaughtered in the two counties last year in what police investigators say was part of a lucrative black-market trade in horse meat.
The industry provides meat to the large local population with roots from Cuba, where the consumption of horse meat is common.
"We want the world to know that in Florida we love our horses - every single one of them - and we won't tolerate them being stolen, dismembered and butchered alive," Jordan said.
She said she hoped that horse owners would pack not only the courtroom but also the footpath for the court appearance of the two men, who have been charged in respect of two specific cases of slaughter.
They are alleged to have admitted to their involvement during police questioning.
They had earlier appeared on August 23, but the case was delayed.
Jordan said the courtroom has been packed shoulder-to-shoulder for that appearance, with some people having to sit on each other's laps.
Jordan said she was probably the only person in the courtroom who actually saw the slaughtered remains of the horses, Linda and King Quizi.
"The only thing that kept me upright was the support and love of the horse people who were there with me.
"In the case of the mare Linda, I saw her four-month-old foal still trying to nurse on his mother's dead, burned body. In the case of King Quizi, I met his owners. It's very sad to see grown men cry, but that's what I saw.
"I also saw a 10-year-old girl who had come to the ranch with her mother to feed her own horse before school started. It's even harder to see a little child cry. The shock this child must have felt when she saw King Quizi's bloody, dismembered and eviscerated body will remain with her for the rest of her life.
"Let's remember that these are crimes not just against the horses themselves, but against the people who love them."
Jordan said hundreds of letters were mailed directly to the judge hearing the case.
Jordan said there was a plea deal on the table: five years in a Florida state penitentiary and some form of probation.
She understood the defendants' attorneys had refused the deal a few weeks ago, but wondered whether they may be reconsidering.
"To me and most of those present, this is not nearly enough punishment for the hideous crimes these two young men committed," she said.
"I also want them to give up the names of the two other men with whom they worked to slaughter the horses, so they too can be brought to justice."
Jordan said she had a message for those behind the slaughter trade: "[To] those who would slaughter our horses, and those who would buy, sell and eat horsemeat, stay away from our horses in Florida. We are speaking out for them, we are protecting them and watching out for them. And we will see that justice is served!"