1) How can you possibly be unable to deal with such a simple concept. If the Amazon consumes just as much O2 as it produces then it provides nothing to the rest of the planet. And indeed, the Amazon DOES consume just as much O2 as it produces.
It is as if you insist on arguing that 2 - 2 does not equal 0. It does! It really does. When you take 2 away from 2 what is left is zero. When you take away the 15% of the Earth's annual O2 turnover (consumed by the Amazon) from 15% of the Earth's annual O2 turnover (produced by the Amazon) you are left with ZERO. Trust me, it really is no more complicated than that).
You calling me wrong on this is insisting that 2 minus 2 does not equal zero. Sorry, but this is not a matter of opinion.
Now I am going to help you out here. I am feeling in a generous mood, after all. Your larger point - that cutting down (or burning down) the Amazon rain forests is bad news on the AGW front is, in fact, CORRECT. You may note that I never said otherwise. However, if you can stick to stating true things rather than nonsense in trying to make your case then your argument will carry much more weight.
Further, you will not be providing fuel to the Trumpettes who look at the types of claims that you make and, finding something clearly wrong, write you off as a moron. Worse, it makes it easier for them to write off everyone who is concerned with the environment as morons. Try not to do that. It makes my life more difficult.
Now, here is the way it is.
1) The Amazon, left unmolested, does NOT increase the supply of O2 to the rest of the world. Nor does it decrease the supply of CO2 to the rest of the world. Please don't say that anymore. It is idiotic.
2) Cutting down and burning down the Amazon rain forests DOES do substantial harm to the atmosphere of the planet. Here, I would advise focusing on the CO2, as the impact there is far greater, both mathematically and otherwise, than that of the O2 change (quiet minimal from any rational perspective).
3) Please refrain from the use of quotes that are as idiotic as this one:
"Since you don't believe me, maybe you will believe the Union of Concerned Scientists:
Even Trumpers would trust the Union of Concerned Scientists over you. The UCS is not idiotic. They are an extremely well-respected organization which has included many Nobel laureates.
You seem to think that an O2 molecule in the atmosphere doesn't count as really being part of the earth's atmosphere if some other O2 molecule is consumed in its place. At best, this is just a weird semantic argument. At worst, it's a misunderstanding of closed versus open systems. I apologize if your argument was the former rather than the latter.
Also, please note that I never argued that the Amazon increases the O2 supply of the world. You kept talking about that. I never did. I only said that 20% of the oxygen we have is produced in the Amazon.
As long as you acknowledge that destroying the Amazon is really bad for the climate, I'm happy. This is a political thread after all and my goal is to make a political point.