It's terrible if calculations are based on stale data from a time when everyone in the US was employed; credit was falling like mana from heaven; homes were ATM machines that magically produced money for vacations, cars, and flat screen TVs; inflation was non-existent, baby boomer stock portfolios were soaring in value; and unicorns were munching on jellybeans and pooping rainbows.
I don't think the calculation are too far off. I think on the example above, you would be in the hole from $15k to $25k per year (the maintenance costs per year are way low considering furniture, electronics, etc replacements on a rental property). If this person really, really wants the second home, they can afford to a take a loss on the property value, and they can easily absorb some annual losses, go for it.
It's a bad financial deal, but if it's good for the emotions and the losses don't bother you or hurt you. No problem.