What you believe 'should' happen is irrelevant. The market doesn't share your moral code.There should be. I have mentioned them on here and elsewhere as pulling forward demand. Though most states have now restricted them to new builds.
Most people support grants and stimulus.
Those who already own houses enjoy the value of their homes getting another boost.
Prospective FHBs enjoy the ability to use the grant to buy sooner rather than waiting.
The complainers are limited to a minority of homeowners who don't want the value of their home to rise (i.e. not many people), and prospective future buyers who were unwilling or unable to make use of the grant while it was on offer, and therefore ended up being even more priced out (again, relatively few people).
So there will be a small vocal minority who complain, and these people will congregate on sites like Macrobusiness, and flood MSM article comments with complaints, but they have no real power.
The majority of voters are more than happy to take advantage of the free money.