I think you could be a little more accurate concerning the logistics of Enoch and what was being quoted and from what source. It was concerning a prophesy of the second coming of Christ. Jude does not define the source of that prophesy other then from Enoch and not any book of Enoch. The prophecy was probably passed down but never recorded with the other OT prophesies in this area of the second coming of Christ. When it was included in the canon of scriptures in the epistle of Jude it was considered inspired because it passed the test of common knowledge that was not only accepted but documented with manuscript evidence, not necessarily or including the book of Enoch but separate from. It is a unique prophesy in that it was not supported directly by OT prophesy but it does not contradict OT prophesy concerning the second coming of Christ.
I am not going to get into the book of Enoch in relationship to Gen 6. It is what it is and there are many different determiners as to what the terms of these scriptures are referring to. Our interpretation of this should never provide a stumbling block to keep anyone in unbelief, so what ever conclusions we come to could be better considered as our opinion instead of our conviction. This stance does not compromise the truth but allows the individual to come the their own conclusions with respect to others. The book of Enoch may give us more information on this issue in Gen 6, but we should use discretion in relationship to God's inspired word and forgo dogmatism in this matter. I have an opinion but think it wise not to share it because of the controversy involved and the effect it could have on those not rooted in the faith.
