This is ridiculous. It is literally part of the job description of PhD advisors to train students and provide research experience. It is not the job of the PhD advisor to totally absolve himself/herself of hiring risk, for god's sake. If you already have 2-3 years of genuine (i.e. truly independent) research experience, you are half way to being a postdoc and the advisor is simply a funding source who should in turn have to pay market rate for employees and have greatly reduced powers over them.