I am willing to bet that the "why" is that they have tons of applicants that don't have 3.0 gpas. I have zero knowledge of the selection process, other than the info gleaned from similar questions on these forums, so I don't know for sure.
That said, you would make an excellent NLO candidate. I would search nuke worker and the various nuclear plant job sites. You will make more money than you would have as a JO or engineer anyway.
But, if the Navy is what you want, then perhaps there is another field you can get into. I am sure the Navy can find a place for someone with an ME.
Goodluck!