Because it’s still considered part of Somalia by international right. Unless Somalia and Somaliland sign a contract that recognizes their border they are basically still in a civil war and recognizing Somaliland is “intervention in internal affairs” of Somalia. Most countries are neutral in this conflict, so they do nothing until Somaliland gets officially released from Somalia.
This is kinda the same situation as with China and Taiwan. Taiwan can’t get recognized without angering mainland China. This is also why Taiwan is the only country that recognizes Somaliland
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