The problem is that there is no distinction of kind between these two types of discrimination. The only difference is of accuracy.

For instance, say I am consciously biased against hiring black people because I believe them to be generally less qualified. This is the same type of discrimination as not hiring a credentialed doctor because I believe them to be less qualified; not only difference that one of these beliefs is factually inaccurate. When you say that activists are only talking about the "bad" discrimination, you implicitly sweep under the rug questions about the factual basis for discrimination; and end up treating questions of fact as if they were questions of morals.

Unfortunately, determining relevant characteristics is incredibly hard (especially if people know what measures you use). Instead we use our intuition and gut feeling. It is important to be aware of inaccurate intuitions we have to improve our assesments. However, there is no easy way to tell a-priori what discrimination is based on an accurate signal, and what discrimination is not.