"Can you explain? I don't see your point. Roberts assigns the decisions."
The majority opinion is written by the senior justice of the majority. If Kennedy had voted for and Roberts against, then Kennedy would have written the majority opinion.
For future cases, it's more important who writes the majority opinion because the wording in the MO will be used. Roberts could have voted in favor so that he would get to use the wording he wanted for this decision.
If anyone ever tells you that you put too much Parmesan cheese on your pasta, stop talking to them. You don't need that kind of negativity in your life.