Sorry but the crux of his argument was how the Court reached its conclusion - by applying a legal argument that they had previously disregarded. And that by disregarding the reasoning they had used to uphold Roe and Casey to overturn Bowers, they had created the means by which to invalidate almost all sex related laws in the future.
Over and over again, Scalia points out that the reasoning applied to overturn Bowers is contrary to the reasoning applied to uphold Roe.
Below, Scalia points out that the Court in overturning Bowers, never goes so far as actually assigning homosexual sodomy the status of a fundamental right, rather they hide it within the "right to privacy".
This is the section on morals based laws:
Over and over, Scalia hammers home that the Court has departed from precedent to advance its personal goals. That the reasoning used to uphold Roe and abortion is now being used to overturn Bowers. One of his frequent points is that the Court says something about society and that the claim is not supportable as fact. But he does not say that the Court should not look at such things. He supports the relevance of looking at such things here:
As society evolves, the judiciary must be aware of changes determine if these changes in society align with fundamental interests protected by the law. That dictates what level of legal protection they are entitled to.
Sorry, but Scalia's point is not that the Court is taking place of the legislature but that the Court is contradicting itself to achieve it's personal ends. And that if the Court was consistent then would have upheld Bowers and allowed Texas to continue criminalizing sodomy. You have to ignore the first 4 sections of the dissent to limit his dissent to the idea about the Court overtaking the legislature.