Yes, mortgages are not universally bad. One of the factors that so far is not included in this discussion on mortgages for retirees is stage of life. For older retirees, which those in the article were, I would not advise having a mortgage for one big reason. It limits your financial flexibility to accommodate unexpected needs. If your retirement budget is maxed out due to a mortgage (i.e.you have to scale back spending on groceries when inflation hits), then if an expensive misfortune comes along, you will be in danger of losing your home. The older we become, the more likely it becomes that we or a loved one will need expensive care or services. How would you pay $2K or more a month for in home assistance, for instance?
If you're a young, healthy retiree, invincible in you own eyes, go for it! Otherwise, look around at your peers to see what life can bring and plan to change your priorities in an instant.