Spam management records help others deal with spam claiming to come from your domain.
Many servers ignore your mail if you don't set them up. Organizations that manage their own e- mail may run an anti-spam gateway server to dust out spam sent to their users. If so, this anti- spam gateway appliance will also check and enforce the DKIM, SPF, and DMARC records of domains that send it mail.
DMARC is designed to fit into an organization's existing inbound email authentication process.
The way it works is to help email receivers determine if the purported message "aligns" with what the receiver knows about the sender...Reduce successful phishing delivery.
In other words, it validates authenticity of incoming emails. Looks like the company is receiving phishing emails from multiple fake senders.