I agree with a human view of Genesis 6:1-4, but don’t expect internal consistency throughout the Bible. 1 Peter 3:20 uses the word psyche for human souls on Noah’s Ark, but the verse before uses the word pneuma for the spirits who were disobedient before the flood. It is inconsistent and confusing for an author to use two different words to refer to human spirits in the same passage, and it makes more sense to assume that these spirits are non-human spirits.
Also, the word phylake (prison) used in the passage is never used for a prison for human souls, but is used for the prison of Satan in the book of Revelation.