It's not the challenges that are the problem. It's the blind assertion that all that work is wholly wrong, and that a completely different solution, one which is untestable, and without evidence except for arguments against the scientific answer, is correct.
It's very hard to win the game when each side is playing by different rules.
The criticisms are not blind and they are made with specificity. They aren't even untestable - Dembski made one I personally was able to falsify with a formal system argument he wasn't aware of. (Specifically, a special subset of complex systems can be shown to meet his specified complexity criteria without having been designed).
The rejections by the likes of Dawkins are blind, and they are not science. They are a personal philosophic view on his own part, a naive and uninformed one at that, they he pretends is science, which he pretends to speak for, etc. The firings and other institutional, rather than intellectual, responses, are also egregious, especially in the case of scientists clearly doing entirely sound work in their own fields, who mention ID or show it glancing respect, largely for their own philosophic reasons, and then get blackballed from all scientific work.
There are decent intelletual arguments against some of the positions IDers have put forward. More to the point, some of them have enough substance that it takes a decent intellectual argument to meet them. Sometimes those are philosophical (most often, in my experience), sometimes formal, sometimes scientific. But slandering them without specificity, arguing against them in straw man fashion for things they haven't said, let alone personal retaliation for professing heretical views, isn't any of those things.
And I see far too much of that from the side of this that pretends to be the scientific side - but that, to me, doesn't speak for science, but for its own pretty narrow philosophic position.
As for openness of evolutionary theory to revision, it is higher when none of this comes up. There are serious weaknesses in the standard paradigm there, that serious scientists have pointed out over the years and currently. But whenever the issue looks like it might be ID, or touches on curricula, all that is just dropped to close ranks, and it is simply pretended in sheer chutzpa that it is all much more solid and settled than it is. That is bad science, and it isn't any better as ideological positioning or public policy.
Bottom line - the IDers are picking at a real scab, and the scab is a scab because the self appointed spokesmen for science are not living up to their own ideals, or their own professed rationality. I don't think the IDers are intellectually right. But their opponents make them look good, by being superficial strident bores.