Earlier quoted context omitted.
Elevated creatinine levels (in absence of supplementation) is a sign of kidney issues. There are many studies showing no reverse link i.e. supplementing creatine damaging kidneys https://link.springer.com/content/pdf/10.1186/s12882-025-045...
Okay but logically kidney issues leading to high creatine does suggest that creatine is not all that good for the body, no? else why would the kidney keep it under control?
Maybe they aren't! But you can't infer that from the mere correlation. Hence that phrase about its relationship to causation.