Can you speak a little to why it doesn't make sense? There are multiple responses on this thread where people are asserting that it's obviously wrong. It's not obvious to me - could you provide some more details?

It makes sense in the wider context of the republican party generally viewing free universal services as a bad thing - the push to privatize education, the push to eliminate or scale back public health care systems like medicare, the push to scale back public pension systems like social security.

A given politician might have their own reasons for wanting to privatize everything (profit, ideology, etc) but it's pretty consistent across the whole party that they aren't fond of any of these programs - I wouldn't actually attribute this to key donors.

Most of that party platform stuff is just fluff.

The more reactionary donors have a real generational hatred of civil service in general and the post office in particular. Alot of fringe thinking from the 1960s and 70s is front and center today.