You can certainly block contacts on YouTube to avoid them from viewing or commenting on your content. Here's our Help Center article which has more info: https://goo.gl/YE2VWv . Hope this helps.
Defensive ? They were just askimg how to block someone. Why are you getting defensive. Enjoy the comtent they bring, companies have the right to allow their content or have their content removed. So just enjoy and relax. Their making nothing from youtube. Have a great night