Why do people act so rude and straightforward when they give their opinion?

Some girl say "I have the rights to my honest opinion and if it's something I don't like or what I prefer, I'm going to say it! If you guys don't like it, don't watch my videos. I'm a straightforward person and I tell it like to is!" I think she was super rude and I just stopped watching her videos. She is too blind and straightforward.