I'm late to this, but this amendment to the Code of Conduct by the IAU
is completely unacceptable and must be rescinded. At the very least it's muddled; at worst it protects those who have committed harassment.

Is refusing to work with a known harasser now an offence?

Note that the email going round states in connection with this change that "The Executive Committee modified further details in the Code of Conduct." This is not within the scope of the Executive Committee as defined by statute 18:

https://www.iau.org/administration/statutes_rules/statutes/

International Astronomical Union | IAU

"The Officers of the Union are the President, the General Secretary, the President-Elect, and the Assistant General Secretary. The Officers decide short-term policy issues within the general policies of the Union as decided by the General Assembly and interpreted by the Executive Committee."

The job of the Executive Committee is to interpret policy, not to decide it.