I believe there is a fine line between a true business expense and a "subsidy" is crossed when the legal definition of a "business expense" is set up in such a way that some purchases are favored over others for no objectively good reason.
That seems to be the case here, since I can find no reason why a new computer, a copying machine, or a 6,000-lb. vehicle would qualify for a Section 179 tax deduction, but a 5,000-lb. vehicle would not.
This isn't a subsidy for the business owner, mind you. It's really a subsidy for SUV and light truck manufacturers.
Keep in mind the limitations on this deduction, both over and under 6,000 lbs have deduction value, but not full purchase price.
http://www.section179.org/section_179_vehicle_deductions.html
For passenger vehicles, trucks, and vans (not meeting the guidelines below), that are used more than 50% in a qualified business use, the total deduction for depreciation including both the Section 179 expense deduction as well as Bonus Depreciation is limited to $11,060 for cars and $11,160 for trucks and vans.
Certain vehicles (with a gross vehicle weight rating above 6,000 lbs but no more than 14,000 lbs) qualify for expensing up to $25,000 if the vehicle is financed and placed in service prior to December 31 and meet other conditions.
The weight requirement for the tax deduction should have been another requirement.
It was meant to give a deduction for true equipment and capital investment (like tractors),
but has been applied to other vehicles under this lazy standard of looking only at the weight.