[1] - http://neweconomicperspectives.org/2014/01/diagrams-dollars-...
What you can't do is print foreign currency. So the component of spending that goes on imports is affected. You can't have a program that prints money to buy people discount fuel if you're not a net oil producing country, for example (this mistake has blown up a number of African economies!)
The next problem is, even if it's true, it may not matter. If the political pressure is too high, governments will proceed from doing what MMT says, and move on to doing what Venezuela did. This may not be a safe road to start down even if the theory is correct, because human nature says that we won't stick to the course specified by the theory.
I could be convinced that I'm wrong, but I want more than a fine-sounding theory that says we can have our cake and eat it too. I want a theory that says how this is actually different from all the times it's blown up in the past.
> government debt is consumer surplus
You are referring to the Sectoral Balances Framework, which says that in aggregate, one sector's deficit is another sector's surplus.
https://en.wikipedia.org/wiki/Sectoral_balances
The MMT response to "the world's debt is soaring" is that means "the world's assets are soaring" as well. Because every liability is someone else's asset. The question is, what kinds of assets are these? If we are talking about debt of governments with sovereign control of their currencies, this is a stable situation. But other kinds of debt could lead to a bubble popping and a financial crisis.
Sounds like when cigarette companies funded studies to 'prove' cigarettes were safe.
They even went full 'USA Freedom Act' by throwing the word Modern in the title.
Those are two non-political red flags. I'll save my personal ideas on economics as this gets into politics.
Modern Monetary Theory itself is a general economic theory, rather than an American monetary or fiscal policy position. The jury is still out on it, but it could suit countries like the US or maybe Switzerland, who have the right economic and currency conditions.
And generally people do have a misconception that printing more money = inflation. For example in the last 2 decades the amount of Chinese currency has increased by more than 800%(https://webofdebt.files.wordpress.com/2018/12/m2-for-China-F...), but inflation remains at 2.2%.