> UBI actually injects money into the economy.
Not unless you're printing it; that's the only way to "inject" money.
> Accompanying UBI would be reducing minimum wage to zero
This is not a "standard part" of all UBI proposals. Some agree; some don't.
> managing inflation by increasing income taxes in higher brackets
Any specific numbers on who would pay what? I may not be rich now, but I don't really like the idea of having to pay a bunch of taxes if I do become wealthy some day.
On the managing inflation part, giving more people more money to spend would make money move around more and quite possibly increase inflation. For an example, let's say I own an apartment building and currently rent a unit at $400/mo. If everyone starts getting $800+/mo, I know I can double my rates without anyone complaining too much. I might not do it all at once, but it seems almost inevitable that this will cause a significant amount of inflation by giving a large class of people more to spend.
> reformation of the health care system
That seems like a whole other kettle of fish. We do have one of the most innovative health care systems in the world, and I'd hate to see that stifled. I had some bad stuff I needed treatment for, which I'd rather not detail specifically. I talked to others in countries with government healthcare who had the same problem, and had to travel here to get treatment as it's a rare condition with most of the good treatments on the bleeding edge. A friend of a friend's mother was diagnosed with stage 2 breast cancer; told to come back later as it wasn't advanced enough to warrant operation.
As someone who's had to rely on treatment not deemed standard by the government, I get twitchy when people mention single-payer etc. Had I been stuck with the treatment prescribed by the gov't, I'd likely be dead.
Lastly, regulating health care prices removes incentives to develop really cool new treatments. They may cost more than your average kidney, but some of the knew cancer biologics are amazing. My parents have friends who have gotten amazing results, though they did have to use a significant chunk of their retirement for said results.