Taylor and Adele have songwriting credits on all their albums and these two artist always claim they write their own songs and everybody believes them. But when Somebody like Beyonce says she writes a song, people don't believe her and claim she stole credit even though multiple producers have talked about how she take control on songs

Why is it that adele and taylor are assumed to write all their songs and nobody questions them. But artist like beyonce have their song writing credits scrutinized and are accused of being thieves.