That's a CAN-SPAM act violation.
FTC: "Tell recipients how to opt out of receiving future marketing email from you. Your message must include a clear and conspicuous explanation of how the recipient can opt out of getting marketing email from you in the future. Craft the notice in a way that’s easy for an ordinary person to recognize, read, and understand. Creative use of type size, color, and location can improve clarity. Give a return email address or another easy Internet-based way to allow people to communicate their choice to you. You may create a menu to allow a recipient to opt out of certain types of messages, but you must include the option to stop all marketing messages from you. Make sure your spam filter doesn’t block these opt-out requests."[1]
Experian was recently fined for making it hard to opt out of their marketing emails.
The actual regulation text:
§ 316.5 Prohibition on charging a fee or imposing other requirements on recipients who wish to opt out.
Neither a sender nor any person acting on behalf of a sender may require that any recipient pay any fee, provide any information other than the recipient's electronic mail address and opt-out preferences, or take any other steps except sending a reply electronic mail message or visiting a single Internet Web page, in order to:
(a) Use a return electronic mail address or other Internet-based mechanism, required by 15 U.S.C. 7704(a)(3), to submit a request not to receive future commercial electronic mail messages from a sender; or
(b) Have such a request honored as required by 15 U.S.C. 7704(a)(3)(B) and (a)(4).
That seems to cover it. File a CAN-SPAM act complaint (spam@uce.gov). Send a copy to the legal department of the sender.
[1] https://www.ftc.gov/business-guidance/resources/can-spam-act...