The commission is this week examining violence and abuse experienced by people with a disability in public spaces, including on the internet.
Ms Barrell, who won two swimming golds at Barcelona in 1992, was born without both legs and one arm and has used a skateboard and more recently a wheelchair to get around.
She detailed "everyday" verbal abuse on dating applications, from students at a school as she walked past, at rugby league matches at Brisbane's Suncorp Stadium and at shopping centres while with her children.
She said fellow sport spectators would approach her when her support worker was not around.
"They see that as their cue to come up to me and start abusing me," she said on Monday.
"They say horrible things like 'I make them f***ing sick' because they are trying to be out here enjoying themselves and I'm ruining their night."
Ms Barrell said she was once ordered to leave a store because the owner didn't want her there and was then removed by security when she objected.
She told the inquiry she has reported verbal abuse to police, shopping centres and the National Rugby League but things "went nowhere".
Ms Barrell also said she has been called "disgusting" on online dating platforms.
Counsel assisting the inquiry, Elizabeth Bennett SC, said there was no single framework for reporting or responding to the full spectrum of abuse experienced by people with a disability in public.
"The hostility of abuse you will hear about ... will take a range of forms but the evidence is remarkably consistent across time, place and disability type," she said during opening submissions.
"The witnesses ... (have experienced) various types of violence and abuse, including name calling, insults, derogatory comments, threats and verbal abuse.
"(As well as) staring, intimidation, non-consensual photography and filming, stalking, sexual comments, sexual assaults, physical assaults like spitting, shoving, hitting and throwing objects at a person."
A 2020 analysis of Australian Bureau of Statistics data found one-in-five people with a disability had experienced stalking and harassment since the age of 15, compared with 11 per cent of people without a disability.
Ms Barrell said she had to be feeling "really good" about herself to leave home.
"You know, good vibes in my head, and strong enough to feel like I can take on whatever the next idiot is going to say to me," she said.
Tasmanian advocacy body Speak Out earlier this year surveyed 110 people with intellectual or cognitive disabilities, the inquiry was told.
More than 70 had experienced some form of violence, abuse, exploitation or bullying in the community by someone they didn't know.
The commission will deliver a final report by September 2023.
