Gaffer Tape said:
As for his statement, it could be referring to either the fact that he referred to the original version as 25% complete and wholly unsatisfied with it (it also being the SE with the most changes), or it could be the fact that nearly all of its plot elements have been retconned by the future films.

That's it exactly.

Lucas never shuts up about how wrong Star Wars77 is. That coupled with his unwillingness to present it properly, acknowledge it's existence, or preserve it - and I can only assume he must dislike it.