As far as I know, he never held public office at all, nor was he ever a GOP candidate in a general election for public office. So unlike KKKer David Duke about 20 years ago (who obtained a seat in the Louisiana state legislature), it's hardly worth wasting the party's effort on denouncing him because he's a nobody within the party structure.
It should be noted by contrast that inane anti-Israel and antisemitic remarks from much more prominent Democrats are nearly never repudiated by their party leadership, especially if those prominent Democrats happen to be black, e.g., Jackson and Sharpton.
Thanks justiceseeker93.