A lot of landlords have no choice. They themselves are businesses, often leveraged to the hilt, with not a whole lot of room to offer grace.
And yes, I realize there are massive REITs behind some of these properties, that have large earnings and reap huge windfalls for shareholders. That doesn't mean they're equipped to receive no income for months during a pandemic. It's sort of the way our economy works: right on the edge at all times.