A lot of the gun channels have been de-monitized. Most of them have recorded promotions for various companies as part of the video. Others use patreon to fund the channel.
It means YouTube believes that advertisers don't want to advertise, or that journalists are running hit pieces on the vertical.
It may be correlated to advertiser demands, but the direct causation isn't there most of the time.
Yes, it is not a good thing for creators, and they must be creative in finding ways to get paid.