"no welfare, looser building codes, no minimum wage, and few restrictions on weapons"
How could this possibly go wrong?
It's just nonsense - to build on a sea platform would require tremendously strong buildings and no owner of such a platform would permit shacks to be built there as crumbling buildings would threaten the platform and its other occupants. The notable difference between a seastead and local building codes is that such agreements on a seastead would be entered into voluntarily, not by fiat backed by violence.
The people who would live and work there would need to be attracted to live on a sea platform, so low-paid workers and destitute beggars aren't even an issue. This isn't a model for society, it's more of a Galt's Gulch.
I still think it's silly to get all the anarchists on a platform that can be sunk by a torpedo (see the Free State Project for a more sensible option) but TFS is written as if by a seventh grader who's heard something about libertarians.