Or to be more accurate, everyone who voted, as your own link suggests, Mr Jones was the ONLY candidate in the Republican primary.
This Article from the New York Times may put it in more context
Mr. Jones, 70, unsuccessfully sought the nomination five times before, and his victory on Tuesday was a foregone conclusion after the Republican Party failed to draft another candidate to enter the race against him.
“Even if only myself and my wife voted for me, I’d win the primary because the Republican Party screwed up big time,” Mr. Jones said in an interview.
Therefore 100% of Republicans who voted, voted for Mr Jones. By same metric 100% of any Democrat who crossed party lines voted for him, 100% of African- Americans, Hispanics, Muslims, Jews etc. who voted would have voted for him.
What is probably more important, is that the Republican party itself opposes him, refuses to fund his campaign and is indeed actively going to campaign against him as the above article goes on to state.
“Arthur Jones is not a real Republican — he is a Nazi whose disgusting, bigoted views have no place in our nation’s discourse,” Tim Schneider, the Illinois Republican Party chairman, said in a statement. He said the party had urged voters “to skip over his name when they go to the polls” and moving forward planned on “vehemently opposing Jones with real campaign dollars.”
A spokesman for the Illinois Republican Party said those dollars would be used to support an independent candidate in the November general election.
and either way he is "unlikely" to win the actual election come November.
The Third Congressional District of Illinois has not been represented by a Republican since 1975, and few people, besides Mr. Jones, believe he has a chance of winning the general election