A man from the village of Brynamman has admitted to 10 offences of stirring up religious hatred against Muslims by posting offensive messages on an Internet website.
Jonathan Damian Jennings, 34, admitted to urging people murder Muslims in a series of rants on the social network service, Gab.
One post included Jennings saying he would be first in line to "Jo Cox" Jeremy Corbyn if he ever became prime minister, referring to the murder of the MP in 2016.
Jennings, of Heol y Gelynen, appeared in Swansea Crown Court via a video link with Swansea prison where he is being held in custody.
During a hearing he admitted to posting messages saying it would be "a good idea" if there was a "burn a mosque day" and if Muslims were placed on top of bonfires.
He also admitted saying that EU remain campaigner, Gina Miller, should be hunted down and killed as well as making threats towards Jewish people.
His barrister, David Singh, said a psychologist had prepared a report on Jennings "which raised a number of concerns."
Judge Keith Thomas said he had read the report and noted that the psychologist had not diagnosed any particular mental disorder.
Jennings has been remanded in custody and will be sentenced on 8 August.