And those taxes will be paid by whom? How does this help the renter?

It helps the renter because it forces the land owner to develop the land with as many apartments as possible, thus increasing supply.

Ironically thats the opposite of how the current system works, where you pay very little property tax if you own a vacant lot and your tax burden increases if you build something productive on the land.

Are you going to let vagrants live in your house then?

Do you not live in your house? The way I read their comment was 'If you own a house then you have high tax. If live in house 1 allotment of rebates if you also own the house equal to 1 house of extra tax.'

If the "vagrants" dont own the house then they get nothing. If you don't live in the house you get no extra. Probably means that small 1-4 family rented dwellings will be come impossible but larger apartment complexes should still be viable.

I was responding to the part about nobody being able to own land.

Not being able to own land does not mean you cannot be sole occupant. It's just that you'd lease it from government (aka the rest of society), rather than owning it outright in perpetuity (and pass to your offspring), to do as you wish with, etc.

This is Georgism, of course. There's a lot to recommend it; I was convinced by Henry George that land ownership is uniquely difficult to defend ethically compared to other forms of property, since it all comes from conquest in the end. I'm not sold on it as a panacea, but big land taxes do seem like a good idea.