1. Having some legitimate interest is not necessarily sufficient - the privacy interests of the data subject can override the legitimate interests of the controller (Article 6.1.f itself), so the controller has to explicitly take the privacy interests of the data subject into account, and the reasonable expectations of data subjects matter. So this can be tricky, as it's up to the organization to demonstrate that their legitimate need outweighs the data subject interests.
2. the right to object of Article 21 applies for this clause, with explicit clarification in 21.2 that yes, people do have the right to object to direct marketing profiling;
3. the controller is required to explicitly inform the users "At the latest at the time of the first communication with the data subject" that they have the right to object to this processing (Article 21.4, and Recital 70);
4. As article 21.5 states "the data subject may exercise his or her right to object by automated means using technical specifications", so this opens the way for specifications such as the upcoming Global Privacy Control header (https://globalprivacycontrol.github.io/gpc-spec/) which would be a legally binding "I object" mechanism.
Because of this, whenever an organization can assert some other basis for lawfulness of processing (e.g. consent or performance of contract) then that would be a safer option than trying to assert a legitimate need.
https://blog.gingerlime.com/2020/sonos-is-spying-on-me-and-y...
on mobile so can’t easily post links unfortunately. EDIT: here’s a couple of links
https://noyb.eu/en/noyb-files-complaints-against-apples-trac...
https://blog.gingerlime.com/2020/does-ios-14-protect-your-pr...