In many ways you are right but over several years now I've seen very few posts from those who successfully have a medium or high carb diet and have diabetes at any reasonable level. There is no doubt that all those carbs convert to glucose but if you have a high natural metabolism or exercise a lot then those carbs will be turned into useable energy rather than stored as fat or lurk in the blood raising BS.
Sure, but that doesn't mean we're dealing in absolutes. The forums aren't visited by every diabetic in the world, they tend to be visited by people who are seeking answers to problems they're experiencing. In many ways, the userbase is extremely biased due to this and shouldn't be used as a source for scientific claims. What we're seeing here is all anecdotal in nature, not scientific, that is also a big difference that needs to be acknowledged. We're likely not hearing from many who are successful with moderate to high carb diets because they're doing fine with their regime, and aren't reaching out for help.
It's the same principle as 'patrons who experience issues in an establishment are the ones who leave the most reviews, but you rarely hear from those who had a flawless experience'. Does that make sense?
I'm definitely not against LCHF, I'm acknowledging it's changed many people's lives, but we can't make scientific statements based on this, and we shouldn't disregard that LCHF is not for everyone, even if it works out for many. That's just as dangerous as the 'everyone needs 160g carbs a day' mindset.
Assessing individual needs should always, always be the leading course of action when it comes to managing anyone's health, whether that is in diet or treatment.