A woman with Down's syndrome was left "offended and upset" when she saw T-shirts sold on Amazon with the slogan "Let's Make Down Syndrome Extinct".
Heidi Carter, from Coventry, said when she had first found the items online she was "nearly crying my eyes out".
Her mother Liz Crowter accused Amazon of promoting hate speech.
The company has since removed the product, which was being sold by a third party, after complaints and a petition signed by more than 25,000.
Speaking to Victoria Derbyshire on BBC News, Ms Crowter said: "I'm just disgusted anyone would want to make them or wear them."
She said it was "not acceptable" for such words to be used, adding: "It is hate speech against people with Down's syndrome."
Down's syndrome is a genetic condition which typically affects someone's learning and physical features.
The T-shirts - which bear a similar slogan to ones referring to coronavirus or cancer - were sold in March and then removed but have now appeared again, Ms Crowter said.
"If you look at the Amazon policy on hate speech, they talk about racial, sexual, religious intolerance and they will not promote organisations with such views, [and] they will also remove listings that graphically portray violence, all victims of violence, but there is nothing in the policy about hate speech for disability," she said.
"So, that will continue hate speech for disability until they change their policies."
In a statement, Amazon said: "All sellers must follow our selling guidelines and those who do not will be subject to action including potential removal of their account."