There are a couple of things there. First off, for federal retirees and how that works, if you got married at 58 but it was after your retirement then it's after retirement. It's basically right after retirement, when you get your first paycheque as a retiree. That's very similar to other jurisdictions and pension plans basically across the country. These kinds of after....marriage types of things are fairly common with pension plans. They've existed in pension plans for ages. That doesn't mean it can't change; that's just the way it's been.
As two members already brought up, it does exist. In Quebec, for example, for marriage after 60 there is no discrimination based on age in the pension plan. In Newfoundland there isn't for the public service or for the CAAT pension plan. Those are the only three examples I'm aware of. The vast majority of plans have something similar to this. Again, as I said, just because it exists, doesn't mean it can't change.