Jim, I can only speak for myself. What you are saying could very well be true for you and bulkbiker, but it's not true for me because I have ulcerative colitis.
To illustrate my point. Last spring I roasted fresh broccoli with garlic cloves, lightly coated with extra virgin olive oil. The next morning I woke to a severely inflamed colon and the start of a UC flare that I could not reverse despite already eating healthy, fasting, having great glucose levels, walking, and losing weight.
At six months I had a colonoscopy and they removed a flat, humped polyp that looked cancerous. Given its size, and based on its known growth rate, I believe it developed and began its slow growth when my diabetes was out of control, prior to learning about and beginning the low carb/keto diet five years ago.
Thankfully, the pathologist found that it was still in its precancerous stage and they're going to recheck my colon next fall to make sure they got it all and it's not regrowing. I was very lucky.
Not sure what you're reading, but according to the research, when the gut microbiomes of UC patients are compared to controls who don't have UC, some bad species are over represented and some good species are under represented. Additionally, there is also research that highly processed plant oils, especially when heated, also likely play a role in UC flares (so I only cook with animal fats now, no plant based oils; lesson learned).
Like it or not, genetics can and do influence what we as individuals can and can't eat. And because I have UC, I will continue to eat plant foods (in addition to animal foods) to increase the diversity of my gut microbiome. All that said, you may not need to. Agreed.