This is a notice that you provide ad revenue to an organization or group that seems to attempt a violent and armed overthrow of the government, and recruits, indoctrinates, and trains mentally ill persons to carry it out. Similar activity might have been behind the murder attempt against Steve Scalise and other Republican Congressmen, committed by mentally ill James Hodgkinson in 2017.
Ads by the Western Union, MD Anderson Cancer Center, Chevrolet, and CHCP (college) were spotted. Archived: https://archive.is/aR313, https://archive.is/SYzzx.
Screenshots are attached. One example: