the rent is already priced to the maximum of purchasing power of the local renters ability.

if landlords were able to raise rent, they would have done that already as its pure profit for them. The fact that they can't, means they will have to eat any marginal tax imposed on them

Landlords are competing with each other, and renters can take their next best alternative. If everything gets strictly more expensive, the next best alternative is not necessarily any cheaper...

The author makes the comment about the land value tax not being able to be passed on to renters in the context of comparing it to a property tax.

If I’m understanding the argument you’re making here correctly, wouldn’t what you’re saying be equally true for a property tax?

I’m not saying you’re wrong, but I don’t think the author would agree with your point since I don’t see how your argument could be true for a land tax, but not for a property tax.