My partner had this and he is a big CW eater - lots of carbs from breads, pasta etc. He had an acute attack with blood in the stool, which was how we discovered he had it. For a couple of years he took psyllium husks to keep it at bay but since I have convinced him to CUT carbs and eat more towards my way - he is still much higher in carbs than me, I go under 50 and he would be about 200 - his symptoms (pain & bloating) have diminished. SO this is the direct opposite to what CW states.
I say don't go looking for trouble, it'll find you if it's after you. Diverticulosis is one of the 'modern diseases' that have become prominent in the last 50 years as modern CW has dominated. I bet Grok didn't suffer from it!