I saw the same article linked on Reddit and there was a debate around correlation vs causation and that we have always been distracted on the toilet.

People that spend longer on the toilet have a higher risk of hemorrhoids, it doesn't matter what reason they have whether its scrolling or reading the newspaper. The bottom line is spending too long on the toilet and if your phone keeps you on the toilet longer than you should, then you will be at a higher risk of Hemorrhoids.