Ian, why not? False claims are a regular reason for taking legal actions against reviewers in many business domains. I wonder why I shouldn't, in general?

Because, this type of behavior is not the norm in academia. When someone tries to sue anonymous peer reviewers it makes international science news. Even if you somehow prevail, the damage done to your reputation by bringing the suit would be substantial.

Yes, you are absolutely right. It is definitely not the norm. But what to do when making false claims are about to destroy one's career? Hmm, I get your point with the reputational damage. Difficult. Thanks for the link, btw.

I am not quite sure whether I am getting it right: The suggestions are to accept bad reviewer's behavior, not to go down a route that is chosen quite regularly in other business domains (because that would be bad behavior in academia), and instead thinking of giving up my academic career. I will think about it. Thank you.

What do you mean by "false claims" and "using strawmen"? Do you mean that the reviewer didn't understand something in your grant or related literature?

@Ian The damage done to the OP's reputation would be terminal, not substantial. Anyone who knew what happened, and that would be everyone in their field, would simply refuse to review their work forever. Without reviewers, all papers, applications, everything they did would sink immediately. That's even without succeeding, merely launching the suit.

Yes, on the one hand, and furthermore, arguing by overlooking key elements and selecting secondary details. E.g. they criticised the oldest of 10 of my publications specified in the proposal, claiming, that I have not published in the field. While 7 newer of the specified publications in exactly that field evidence the opposite, suggesting rather convincingly, that I am experienced enough to work on the proposed topic.

2 reviewers is pretty much the norm. As is the norm that criticism is focused on - if you briefly skim a paper, proposal ... you might not notice anything wrong or inconsistent. For example, take publications from your comment - first reviewer might have seen 17 publications (candidate is good), the other saw 10 irrelevant ones (candidate is trying to mislead or exaggerate experience in the field).

This scheme allows one to specify max. 10 pubs: 8 of them are preparations for my planned work on the proposal. The 2 other are in the highest IF journals in my field, evidencing broad knowledge in the field of my proposal. All 10 are first+lead-authored.

Can you resubmit? This might depend on the particular grant, but often it is possible. If this is not a "revise-and-resubmission" and hence there's no opportunity to include a rebuttal, you could formally make a new submission and address some of the remarks in your revision. But yes, contact the program manager first of all.

@Mario Is it not your responsibility to highlight your experience besides in the CV? I'm used to grants saying things like "In previous work, we've done ABC; in this work, we will XYZ" where the link is made directly for the reviewer. A claim that you haven't published in the field is an expression of opinion, not fact.

"being knowledgeable on the topic" is not grounds for declaring yourself in conflict for the review. "Certain conflict of interests" certainly are, though.

@Mario Grants are never a sure bet. How do you think that this has destroyed your career, when it's something that happens to many people during their careers? And if you lose out on one funding round, an improved submission at the next funding round (which is written so people can't misunderstand or misrepresent it!) might well be accepted.

You may want to read this Wired magazine article titled, "Peer-Reviewed Scientific Journals Don't Really Do Their Job" (wired.com/story/…).