Anti gay marriage ballot initiative: amendment or revision?

Apparently, it matters a great deal whether the proposed California anti gay marriage ballot initiative is an amendment or a revision to the California constitution:

[...] California citizens can amend the Constitution by ballot initiative, but they cannot change the fundamental parts of it (such as fundamental rights granted, and fundamental workings of the government) by ballot initiative. Changes of that scale are called revisions, and revisions can only be accomplished by a constitutional convention and popular ratification of the changes made by the convention, or by the Legislature passing the change and submitting it to the electorate for popular ratification.

With the CA Supreme Court ruling on May 15th, marriage was reaffirmed as a fundamental right in California, and furthermore, sexual orientation was placed into a protected category, subject to strict scrutiny. Therefore, a ballot initiative cannot take away that fundamental right, because that kind of a change is a revision of the Constitution, necessitating a constitutional convention. Additionally, any attempt to do so will come under the heading of strict scrutiny, which means that the government must show a compelling reason why it is excluding people from marriage. That cannot be done; there is no compelling reason. Ron George and his fellow justices made sure that they eliminated those arguments in their majority opinion.

Question: isn't it weird that you can amend the California constitution with a ballot initiative that only has to pass by a simple majority? (Am I right about that?) Shouldn't it be harder to amend the constitution than that? The federal constitution requires 2/3 of each legislature and 3/4 of all state legislatures (if I remember my civics correctly). It seems to me that it should be harder to amend the California constitution than to simply pass a ballot initiative. Are there progressive causes that should be taking advantage of this?