Earlier quoted context omitted.
The point is, the apartment owner pays property tax and collect rent from tenants to pay for that. If property taxes go up, property owners raise rents to compensate. So the tenants are paying the property tax, albeit indirectly.
If the tenants will pay and it doesn't break any rules, why not raise rent before taxes go up and pocket the extra? (serious question)
Its actually much more complicated then that, depending on factors such as the propensity of landlords to cease renting out units if their profit decreases, the propensity of renters to shift to smaller dwellings in the face of rent increases, etc.