That behavior is against the official server rules and you should report the clan. The proper procedure for reporting is in the post that describes the rules:
Official servers' guidelines
Introduction
Conan Exiles has thousands of official servers across several platforms and regions. These come with certain rules and strict enforcement.
By playing on an official server you are expected to follow the guidelines below. Support will do their best to honor these guidelines.
Please read through and consider the spirit of the guidelines, not the specific wording.
We reserve the right to modify these rules. We will notify players in advance of any …