Why do some people say Christina Aguilera’s is one of the best singers?

Christina Aguilera fans are going to be pissed when I say my unpopular opinion but I don’t give a care. She can’t sing! All she does is scream in her songs and she’ll try to strain her voice. No wonder she wasn’t as big as Britney Spears. Christina’s voice is horrible and I don’t understand why some people like her voice so much. She over singes songs and it’s garbage. Hate to say it but Britney Spears and P!nk are better vocalist than Christina Aguilera! Yes I said it! Don’t @ me! It’s my opinion and I’m entitled to it.