Why Sage Advice states that Shove & Grapple are not attacks?

The grapple option in the Player’s Handbook is an attack, but it uses an ability check in place of an attack roll. https://t.co/qNh1wlyqff

— Jeremy Crawford (@JeremyECrawford) May 6, 2015

@oilpainting71Does the sage advice on ability checks contradict this? It states that shove & grapple are not attacks? There’s no contradiction. They are unusual attacks that lack attack rolls. @warhuck

— Jeremy Crawford (@JeremyECrawford) June 3, 2015