I believe that the work of (e.g.) Stephen C. Meyer is science, as an unbiased reader will find by examining his arguments.
Meyer's work boils down to a God of the Gaps argument, one of the hallmarks of pseudoscience. If you think this is wrong, then point to any ID argument that doesn't boil down to "Evolution is false, therefore it was intelligently designed". It gets even worse when you look at Meyer's specific claims which many have turned out to be false (e.g. lack of pre-cambrian life and transitional forms).
ID is pseudoscience because it can't stand on its own. ID can't produce positive evidence for its own claims. I have never seen a scientist try to support the theory of evolution by saying "There is no evidence for intelligent design, therefore it had to evolve". Not once.
“I argued – based upon our uniform experience – that sequences that are both complex and functionally-specified (rich in information content or specified information) invariably arise only from the activity of intelligent agents. Thus, I argued that the presence of specified information provides a hallmark or signature of a designing intelligence.”
Where is the evidence that supports this argument? How does one measure complex and functionally-specified sequences? How does one falsify his hypothesis?
Scenario I: Suppose that in 1835 ( I am altering history for the purposes of clear illustration ) archaeologists had dug up from the sands of Mesopotamia the first cuneiform tablets seen since ancient times. “Extraordinary,” says one scholar, “an unknown script. I shall copy these markings, publish them, and perhaps soon we shall decipher them and increase vastly our knowledge of ancient times.” “Oh” scoffs a colleague, “what a fanciful notion. These are just natural formations, brought about by the action of wind and water.” Who would be taken seriously? The second scholar would be laughed at and dismissed. Why? Because cuneiform, even to those who cannot read it, is clearly intelligently designed. The hypothesis of artifice would be the only one taken seriously.
Scenario II: biologists discover a bewildering array of complex structures and processes in the cell: Flagella, mitochondria, the genetic code itself. One biologist says, “This stuff looks intelligently designed to me.” His colleagues respond with outrage. “That is unscientific” they yell, “intelligent design can never be a legitimate explanation in science. It is of the nature of science that we employ as hypotheses only natural processes.”
The difference is that we can observe new cells arising through natural processes. It's called biological reproduction.
The moral of the story is that we often recognize design without trouble, but when the design hypothesis offends a cherished dogma – in this case, atheism – suddenly no amount of evidence for design is deemed sufficient.
Evolution is not atheism. There are tons of Christians who accept evolution as the process by which live diversified.
With regard to your third question, Taq, it is true that intelligent design is hard to falsify. In the case of the cuneiform tablets, to show that they are not intelligently designed, one would have to provide a detailed scenario of how they might have been formed by geological processes, and preferably show through experiment that wind and water could form such things. You are welcome to raise the question of burden of proof if you wish, but I warn you that the issue is more complicated than any treatment I have encountered.
I can take a single bacterium and put it in broth. The next day I have billions of new bacteria, all through natural processes. ID falsified.