Because long ago it was "she singeth" (I don't know why) and "she sings" sounds like that.
lala sings it prima j sings homegirls/
Urbandub sings it.
who sings that thing you do???
Joe sings himself.
noone sings that
I Sings was created in 1999.
The song? Joi sings it.
Usher sings omg
Ryan miller sings it
Jesus sings to the sky
Rey Mysterio sings it.
Avril Lavigne sings this