I didn't see this said in the article explicitly but if the index funds start selling rather than buying, stocks like Apple will probably be OK, but some other

I didn't see this said in the article explicitly but if the index funds start selling rather than buying, stocks like Apple will probably be OK, but some other stocks that have been propped up by the index funds may have no bid and they can crash. This of course leads to more people exiting those stocks and potentially a vicious spiral. I supposed this could also effect the whole index.