Because it may be cheap, available, and gasp aligning with China might not be so bad overall compared to alternatives.
What about the Japanese manufacturers, you might ask? Well apparently there's so much Sony Xperia smartphone stock that NTT DOCOMO is selling them for just 10 yen each with the purchase of a new contract.
I'd say the only reason we don't see Huawei in English-West is because we were more preemptive in kicking them out of our markets.