I am having a hard time making the point that ID is just as testable as blind evolution..

That's because you haven't made the point. Let's examine something you claim as a basis for your argument:

If an event is exceedingly improbable - it probably never happened.

Probability theory doesn't say that at all. Probability theory says that a single roll of the dice/flip of the coin/division of the cell has a certain likelihood of each possible outcome. If you've got billion-to-one odds against something happening, then it probably won't happen on one try. But after a billion tries, it's quite likely that the event in question actually does happen. I think you really know this. The fossil record indicates that simple algal life (the stromatolite) goes back half the age of the earth. When you have billions or trillions of organisms reproducing at the rate of every few days, perhaps every few hours, then lots of seemingly unlikely things happen. Extend that over hundreds of millions of years, and a few of those mutations might actually turn out to be useful. Then when some clever pair of organisms invents sexual reproduction, then the combinations go through the roof. Those folks that play poker don't expect to get a royal straight flush on every hand, but it does happen from time to time. Apply environmental pressure (temperature, oxygen, food, etc) and you get adaptation and evolution. Danged if it doesn't look intentional.

As a side note, I have been involved in oil exploration for over 25 years and I have seen numerous geological theories fall by the wayside in that time. Geologists (at BYU and Utah) in the 1960's were adamantly opposed to continental drift and would essentially heckle anyone who gave it credence as I witnessed at a presentation made at BYU. Continental drift is now the accepted theory. So much for objective science.

And the anti-drift people gradually became comfortable with drift, accepted the theory and moved on, doing good science along the way. Most of the religious community did the same with evolution, focusing on how humans should live in the world rather than outmoded mythology on how it came to be.