To date, IDists make claims about how random genetic mutation is always bad for the changee.
I haven't been able to figure out yet just hwat IDists do claim. You may be setting up a strawman here.
The little I have read of ID ideas is that
some steps in the diversification of life can not happen through individual evolutionary steps and must have had some sort of "outside" intervention. I'm not sure there is more to it than that. Clearly some of the IDist otherwise accept an old earth and a full range of evolutionary change. What others want to say I'm not at all sure.
I don't think that the idea that all mutations are harmful is part of anything that could fairly be called ID. Can anyone clarify this?