I want the option to dislike

Why is it that most websites allow people to like things, but not to dislike things. For example, when I see something truly horrible on etsy, why is there no option to give negative hearts. Are people's egos so fragile that they could not handle knowing that people do not like what they do? If I am on facebook, and someone has a status of "doing homework" or "dog died this morning :( " I have no optioon to dislike that these things have happened.

All I want is the option to dislike.