I happen to agree that the Democrats are evil and would never vote for them. However, this was in place long before the Vietnam War. It came into being around 1890 when a congressman from Missouri (who'd been a Confederate general) seized an opportunity to deprive Union veterans of their pension since Confederate veterans didn't recieve anything.
Since I'm one of those disabled retirees who loses $606.00 dollars a month from my retirement as a result of serving my country as an Infantryman for 26 years (and voting Republican all my life)let me explain it like this.
Let's say your injured on your job and received Workmens Compensation. Eventually you retire and now your employer takes back one dollar from your pension for every dollar you received as Workmans Compensation. No, I have no love of the Democratic Party but I wish the government would do the right thing and pay us retirees our retirement check. Congress has no problem collecting theirs.
Let's say I am injured on the job sufficient to retire me. I will get 60% of my last annual rate until my regular retirement based on my high-three equals that amount. Then I get regular retirement.
In effect, 100% of my workman's compensation is taken away to finance my regular retirement.
Isn't that what happens to military retirees who are disabled before retirement?
BTW, if that Confederate General was politically motivated, he was undoubtedly a Democrat. So, let's blame this on the Dems from the very beginning.