As a Jew whose parents support Trump (and Republicans in general), it won't erode his support. They'll make excuses as to what he really meant while saying "he's not anti-semitic because he supports Israel."

Of course, Israel isn't American Jewery. Trump "supports Israel" because his evangelicals need Jews running Israel for Jesus to return. He doesn't care at all about Jews and the Republican party is going all in on "this is a Christian nation and any citizen who isn't Christian can pound sand." (They also like Israel because it gives them a place they can say they'll deport all Jews to.)

But my parents are blinded by "supports Israel" and so they ignore everything else surrounding this.