Alter means 'alternate state of identity.' This phrasing implies that we are an identity, rather than living beings.
Yes, every individual has an identity, however that does not make that individual the identity, but rather the holder of the identity.
Saying we are "alternate states of identities" implies that we are all just separate identities that a single consciousness holds, which is not true, because we are all separate individuals with separate consciousness, even if we share a brain.
Idk if this makes sense, but in other words, its like calling us personalities- we have personalities, yes, but we arent personalities in of ourselves.