From a strictly utilitarian point of view (the favorite view of this website), since there's more tenants than landlords out there, shouldn't we err on the side of protecting tenants from abuse rather than the other way around? You can't have it both ways, so you have to do something.
Because it's high risk to rent out units, many who don't need to, don't do so. I know of several who don't do this but could. They have extra rooms in their first floors of their houses that could function as a more affordable in law suite for example. They have jobs, careers or have stress tolerance issues and thus have much better things to do than to deal with nightmare tenants.
These tenant protections come up because governments want their cake and eat it too. If you live in a functional housing market the need for tenant protections also decrease, because more people can afford to rent places!