Supreme court decision or no, Article 1, Section 7 seems pretty clear on the point. It's not surprising that the courts would rule after the fact that the president doesn't have to sign such proposals. If they had ruled the other way, that would have invalidated the first ten amendments. I know people seem to have this image of judges as being completely detached and sublime in their thoughts, so it might come as a shock to discover that they really are human with human frailties, and as such I'm sure they wouldn't have felt too comfortable at the thought of ruling that the BOR doesn't actually exist. So they would have done anything, twisted themselves in any direction, to avoid having to rule that way. But that doesn't make it right.
Court, schmort. It is quite clear from the text of the Constitution that the President has no direct role in the amendment process (though of course he may use his bully pulpit to exert influence):
Article VArticle 1, Section 7 pertains to the passage of bills into statutory laws, and has nothing to do with the amendment process.
The Congress, whenever two thirds of both houses shall deem it necessary, shall propose amendments to this Constitution, or, on the application of the legislatures of two thirds of the several states, shall call a convention for proposing amendments, which, in either case, shall be valid to all intents and purposes, as part of this Constitution, when ratified by the legislatures of three fourths of the several states, or by conventions in three fourths thereof, as the one or the other mode of ratification may be proposed by the Congress; provided that no amendment which may be made prior to the year one thousand eight hundred and eight shall in any manner affect the first and fourth clauses in the ninth section of the first article; and that no state, without its consent, shall be deprived of its equal suffrage in the Senate.