Spain’s AEPD (report 0011/2014) said that information with a link to a privacy policy, plus the absence of an objection, is not enough for pixels in advertising emails: active consent is needed beforehand. A link to turn tracking off works after the fact, so it does not meet that requirement.
The legal basis for tracking, the information recipients must get and the proof of consent belong to the company that decides why and whom it tracks. HawkOpen does not promise that any particular use of tracking meets the GDPR.
What the notice does: it tells every recipient that the email contains HawkOpen tracking elements, and no setting removes it. In the Mailtrack case the AEPD looked, among other things, at how recipients were informed, and the fact that the information could be removed was one element of its assessment.
Where rules that require consent apply, tracking may start only after that consent has been obtained. The link in the message lets the recipient withdraw consent later.