Because there are all sorts of insecure malware/adware out there. They're all various levels of evil and a known quantity of badness. Lenovo is a company that

Because there are all sorts of insecure malware/adware out there. They're all various levels of evil and a known quantity of badness. Lenovo is a company that you paid your money to to buy a laptop. It shouldn't come pre-infected with something that compromises your security and privacy.