If anyone understands the reasoning behind the US capping your deductible net capital loss in any tax year at $3,000 vs allowing your full capital losses to be offset I'd be interested.
A more sophisticated argument is that since you can control capital losses by choosing which assets to sell you would be able to manage your taxes. With enough assets and some planning you could never pay taxes despite having a large income.
The $3,000 cap prevents this. Similar approaches are used throughout the tax code to prevent abuses.
As in people ascribe ongoing debates to the system being broken, yes.
Literally in this thread we have good arguments for reducing capital gains tax exclusions and special treatments and arguments for.