TFA gives an example of amortizing the cost of a $2,000 server with a 4 year life. If you did not amortize the cost, you would have a "bumpy" expense with a $2,000 charge in Year 1, then $0 for the next 3 years. It is more convenient to smooth out the cost of the server over the expected lifetime, instead treating it as a $500 cost in each of the 4 years' of its expected life. Essentially treating it more like a service or pay-over-time situation.
But employees don't work like that. Employees don't have multi-year expected lifetimes which you are required to pay for upfront. In the US at least, it is fairer to say that an employee has a 2 week expected "lifetime". If you stop paying them, they will go somewhere else.
How can you take something that you essentially lease 2 weeks at a time, and amortize it over 5 years?
At least that's now how the IRS sees it. Similar to buying machines to create a physical product.
Maybe they read all these articles about developers working in a feature factory.