As hunter/gatherers the diet was mostly hunted animals(protein/fat) and some occasional carbs from gathered fruits

Many modern H-G cultures are the opposite, with the majority of calories coming from fruit or other mostly-carbo plants. It's less clear what prehistoric people ate (except that they had widely different diets at different times and places; there's surely no single "paleo diet"). But at least many non-HG historical people who eat or ate a "traditional" diet which is mostly carbohydrates (with rice, corn, or maize as staple foods), where only the rich ate meat often, had a much lower incidence of modern metabolism-related disease.

Lots of people develop health problems(overweight, diabetes) that has to do with an excess of carbs.

If only it were that simple. But "what causes obesity or type 2 diabetes" is far from a settled question. Many people believe excess (refined) carbs are partly or mostly to blame, but it's not quite clearcut.

Carbs are appetite stimulants, causing overeating.

Everything that stimulates the appetite potentially causes overeating. All types of food, incl. protein- or fat-rich food, can be stimulating. Different people have different tastes too.

It's easy to overeat in carb in general, they literally just melt inside your mouth, whereas with meat you have to do real work(chewing and digesting). Try eating just meat/fat for one week, I found this to be almost impossible.

Well, people used to a paleo-like diet may love meat and find it "almost impossible" (i.e. not fun) to eat lots of carbs. What people like has to do with what they're used to, what diet they were raised with, how food is prepared and spiced, etc. What people like is not in any case an indicator of what diet is good or bad for them.