With regards to the former, if Singaporeans don't own the flat then how come we can sell it? To me, you cannot sell what you do not own.
But then again, HDB themselves also refer to owners as "lessors".
And also just to highlight that even those leasehold private property is also the same in HDB in the sense that after the lease term expires you have to return it to government. So are they owners or lessors?
Sorry, if any of my above is wrong. I no expert, just providing a man-on-the-street view.
You don't own the flat, you are a lessor. You only own the right to hold the physical property, which is the lease from HDB, but you do not own the physical property. So whatever is sold related to the physical property is when you hold the lease, and based on that lease you hold.
You can only hold the physical property based on the lease issued by the HDB only, because the HDB flats are under the assets of HDB. If you don't have the lease issued by the HDB, you can't hold the physical HDB flat. You cannot just claim ownership just as whatever you want.
You don't sign a sales contract with HDB, you sign a lease agreement. Technically, you are just a lessor.
HDB has the right to repossess the flat as and when they want. They do not en bloc to buy back your flat because the flats are their assets, not yours.
You can't do whatever you like after you got the flat. You have to subject to their terms and conditions, rules and regulations if you want to do anything you want with the flat, like rent out immediately, sell immediately, etc. So technically it's not true ownership, it's basically a lease with extended conditions.