Donald Trump's recent attacks against the U.S. Post Office are very disturbing (and not new). Certainly his hatred of Amazon and its owner, Jeff Bezos (owner of the Washington Post) are one reason. Others speculate that mail-in ballots would be more problematic with a crippled postal service.
Be assured that anything Trump does has self-serving motivations.
I would stand outside in a blizzard in November to vote against Donald Trump.