What's worse, parents of other sick children being treated at the hospital where Charlie Gard has lived most of his short life also claim that they have been "harassed and discomfited" by those opposed to the Great Ormond Street Hospital's stance in terminal baby's case. Many of these messages are menacing, including death threats.
Charlie suffers from the rare genetic condition, which causes progressive muscle weakness and brain damage.
After the hospital's lawyer, Katie Gollop, told a judge what doctors thought of results from new scans of Charlie's brain, the baby's mother, Connie Yates, burst into tears, and his father, Chris Gard, yelled "evil", according to the association.
Staff at Great Ormond Street Hospital (GOSH) in central London are said to have received thousands of abusive messages from supporters of Gard's parents, Connie Yates and Chris Gard, who are contesting the hospital's decision to remove the infant's life support.
But the case was reopened earlier this month at England's High Court after two overseas hospitals approached GOSH with possible evidence of alternative treatments that might help Charlie's condition.
Parents visiting their seriously unwell children have also been harassed, including on the grounds of the hospital itself, she said.
Ms MacLeod said: 'In recent weeks the hospital community has been subjected to a shocking and disgraceful tide of hostility and disturbance.
"But the abuse of staff at Great Ormond Street Hospital outside the hospital and online is totally unacceptable". His parents want to take him to the United States for pioneering treatment.
But Charlie's parents have garnered support from President Trump, Pope Francis and US lawmakers.
Doctors at GOSH have said there is no realistic prospect of improvement and Charlie should be allowed to die with dignity.
Mr Gard added: "We have always acted in Charlie's best interests and we have never slated gosh publicly, in fact we have been grateful to the staff for their care despite some conflicting issues".
Friday's hearing was the first time his parents were told about the latest results in the crucial test of Charlie's brain function.
American specialist, Michio Hirano, a professor of neurology at Columbia University Medical Centre in NY, travelled to London this week to examine Charlie for the first time and discuss the case with Great Ormond Street doctors.