...foods and low calorie food, differences in activities and goals, saying "A healthy highly trained endurance athlete or bodybuilder exercising several hours per day is going to have very different needs and tolerances than a sedentary diabetic overweight office worker.", etc.

Keeping in mind that "Fat loss is ultimately about calories in versus calories out" is important because, while it may not be a good guide to specific food choices and exercise plans, it is useful for setting boundaries that people are all too likely to ignore when they get tempted by hype about "fat-burning foods" and infomercial exercise programs that supposedly burn away pounds and pounds of fat "in only twenty minutes per day!" Too many people are either causing themselves unnecessary grief by avoiding foods that have been unnecessarily demonized, or are failing to lose weight because they consume too many calories while expecting some "superfood" that they're eating to "melt" their fat away.

As long as you're getting the nutrients you need, the most important thing about food choices for people with weight problems is managing hunger. That doesn't change the essential truth about "calories in, calories out", however, it just changes how much will power is needed to prevent excess calories from coming in.

To the extent that food choices may actually change your metabolism, change the rate at which you burn calories, if such effects exist I don't know how well proven these effects are, and I doubt that these effects ever amount to much more than tinkering around the edges of the calories in/out balance sheet.

As for red meat...

I looked at many of the studies that your search brings up, and what I see is a lot of "could", "may", "is associated with", etc. Some of the studies are about particular metabolic reactions, but not looking at the big picture of what's actually going on when people eat red meat. Other stuff is bigger picture, but so "big picture" that it's talking about comparing diets that are greatly different not only in the consumption of red meat, but many other ways at the same time.

No, I certainly didn't go through pages and pages of matches from the search you suggested, but if the OP article's author's point was that there isn't a solid body of research that shows a clear, causal link between typical levels of red meat consumption and specific health problems, that seems to be the case from what I've seen.

Perhaps some people want to "play it safe", avoiding certain foods even when there's only one or a few reported "could", "may", and "is associated with" problems, but I suspect if you take that route, pretty soon you'll be afraid to eat anything -- or, more likely, in order to avoid starvation, you'll start to rationalize believing the research that fits your preconceived notions of healthy eating, and dismiss the studies that would attack whatever is left that you like eating until there's more evidence.