While none of us can know precisely how Trump treated his losses on his Federal taxes, these provisions are actually reasonable (IMHO) in general. Owning property is not a no-risk proposition, whether on a small scale or large. And of course large businesses use these provisions more than small ones, that is because they are large, and their asset values are larger.
I am no supporter of Mr. Trump, but he put his money at risk, and lost big. If a small business owner of a tanning salon, or food outlet, loses their investment, as many do, they can legitimately deduct these losses from their taxes. If they lose say $50,000.00, a not uncommon occurrence, they may not have a payable tax liability for 3, 4, 5, or more years. This is not an injustice.