I guess because they lack knowledge of bitcoin, so they hate bitcoin. You can provide proof of your income from bitcoin, and they will start thinking about bitcoin and in the end they will choose bitcoin.
In addition, it could be affected by negative news about bitcoin or have had bad experiences with bitcoin, caused by a lack of basic knowledge of the world of cryptocurrency. So, it is important to build knowledge first before deciding to invest or trade with cryptocurrency.
And, the simplest way to silence a person who hates bitcoin is to show the results you get from cryptocurrency, its simple.