It's not their home.
They can't walk in, wipe their shoes on the hallway rug, make a pot of coffee, use the bathroom, turn on the TV, and take a nap on the couch. At least not without their tenant's invitation.
When they chose to rent out the house they yielded some of their property rights. The old landlord argument that "it's my house I should be able to XYZ" doesn't hold water.
Did you know in Australia it's normal to give your landlord a tour of your house every 3 months to prove you haven't broken it? That's completely ridiculous.
Add to that loss of rents for multiple months (while the landlord has to pay mortgage, insurance, taxes) and damages to property, and now you're asking a landlord to pay tens of thousands of dollars of their money.
Throwing around general statements like these when you don't actually know about the topic doesn't help the conversation.
Renters insurance primarily covers damage to _their_ property and only some narrow cases of damage to the unit (e.g. fires, flooding, etc.). A deadbeat tenant also will likely not be paying for insurance past the first month.
To give you some perspective, the eviction process costs around $20000 right now in legal fees. And you'll need to pay them, because the commie "housing justice" redistributionists know all the procedural tricks to delay and derail the process. Even in the best case, you're looking at a year of delay, and it can be more than 2 years for people with children. So that can be $100k+ of loss.
No insurance company is going to assume these kinds of risks without sky-high premiums.