I don't feel the same way towards my niece as everyone else does
Why do you feel differently towards her?
I think she is ugly.
Well, family members are supposed to be supporting and love each other. I think you should revisit your opinion and perhaps spend some time with your niece to get to know her better. Otherwise you're just judgy and hasty.
I don't need to. All children are ugly.
If you think children are ugly you really need to spend some time with them to understand how innocent and beautiful they are. It's wrong to make such generalization and call them ugly.