It is stimulative because some of those savings in taxes will be spent by the person; it's just less stimulative than it would be if you gave it to someone with low income, who would probably spend 100% of it. So it's certainly stimulative, but just not quite as stimulative.
I guess you can't have a budget that focuses exclusively on one set of Canadians. You have to have a budget that has policies for all Canadians, and I guess the government made a trade-off and decided to provide some tax cuts for the people at the top. It also benefits people at the bottom as well.