But this is exactly what the warmists always do - try to close down the debate.
I fear you've misunderstood.
It's not about trying to close down a legitimate debate. Please try to understand that the science is well established. The evidence for man-made global warming is simply overwhelming. For all practical purposes, it is an established fact. Amongst scientists, there is no serious debate about whether it is happening or not - not because of any conspiracy to stifle debate, but because debating whether man-made global warming is happening would be a bit like debating whether 2+2 really does equal 4 or not, or debating whether or not the holocaust really did happen, or debating whether or not bacteria can cause illness. The science (or, in the case of 2+2, the maths) has been done, and the result is known beyond any reasonable doubt. Those who would try to convince you that there is significant doubt about whether man-made global warming is happening are - quite simply - whether knowingly or unknowingly - misleading you.
Of course, debating what we should do in response to global warming is a separate question and
is a perfectly legitimate subject to discuss and disagree on. And similarly, seeking explanations of how the science works and on what basis scientists have come to their conclusions is also quite legitimate and understandable (although full answers to that are likely to be fairly complex). One of the saddest things (and, frankly, one the most frustrating things) is the way that so many people, including some politicians, instead of addressing the legitimate issue of 'what do we do about climate change' have chosen instead to try to find ways to smear or debunk the science itself, or the scientists - in the process, convincing many innocent people (including, I'm guessing from your comments, yourself) that there is somehow some significant doubt about whether global warming is happening. There really isn't any doubt about it.
Also do you really think the self-appointed climate scientists (aka "activists") really know what is going on either?
As it happens, I used to work as a research scientist (in physics, not climate science, though I had contacts in climate science - so I'm in a good position to know how science works and how the culture works. I can assure you the many thousands of scientists working on climate science in various universities and research institutes around the world, are, on the whole genuine scientists, no less so than scientists working in physics, biology, or any other scientific field. I don't know what you wish to achieve by describing them as
self-appointed climate scientists (aka "activists"). (Obviously there are activists involved with the political side of campaigning for action on climate change, but that doesn't change the fact that basic climate change data is researched by scientists).
If this were really science, they wouldn't confuse causation and correlation. They would allow independent scrutiny and sharing of data (that we taxpayers paid for). There would be peer review. They wouldn't conflate three different things - climate change, global warming and AGW.
Unfortunately the whole thing stopped being "science" years ago, and has now become a belief system.
What you are quoting there is fairly standard stuff from many of those who seek to deny climate change by trying to smear the scientists. And I'm afraid on the whole it is just that: Unjustified smears. Research establishments and research journals tend to have very well established mechanisms for peer review etc. There's no reason to think there's any mass conspiracy to prevent sharing of data - indeed much of the culture of science depends on others independently reproducing your results to verify them.