But why are all orcs warlike? If it's not by nature then why are all orcs from multiple locations in a content warlike?
Why are they still wearing crude armour and weaponry when dwarves and elves have had better technology for hundreds of years?
If you rule out "it's their nature" and orcs are just as intelligent and capable as humans and halflings, thenand then why haven't they joined with the other societies?
Historically, there's virtually no such thing as just "joining other societies." The way rival societies "join" is for one to subjugate the other (not always via outright warfare), and the winners to treat you more like the Persians treated the Ionian Greeks than, say, the Manchu treated the Dzungar. Because while sometimes, the conquerors judge you capable of being incorporated into the empire...sometimes, they decide it's not worth the trouble.
If you didn't get incorporated into the Cloud Person Empire, it's for the same reason the Picts never joined the Romans: they were never conquered.
It becomes an Eberron situation where the humans came in and took all their land and ruined their civiliation, and have prevented them from rebuilding. A colonial narrative where the orcs are opressed and systematically knocked down to prevent them from founding their own kingdom.
That doesn't at all follow. If some technologically inferior tribe of people is never really conquered, they often don't adopt the ways of their rivals. To go back to the Picts, they never started acting like Romans. Ever. There's no reason to believe human societies are on any kind of convergent path. Written language, agriculture, a centralized state...these ideas largely spread via one group of people kicking the absolute naughty word out of another.
You often find these ingredients:
1. Technologically inferior people whose
2. Social organization prevents them from urbanizing and developing intensive farming but
3. Inhabit land that more technologically sophisticated societies don't really want and
4. Additionally have an aggressive warrior culture so taht
5. Conquering them means shedding a lot of blood with little payoff so they
6. Don't get conquered, and
7. Often plunder the outskirts of civilization
8. Which the central Cloud People don't care about all that much anyway
Maybe that's your setting's orcs.