Should? Hell No.
They do not have to disclose that affiliation in their profile. What people write in their profile is their own business. Of course, they're free to disclose such affiliations in their profile.
However, they do have to disclose their affiliation when answering and the affiliation has an impact on way people will read the answer. It's actually in the help pages already.
However, you must disclose your affiliation in your answers.
Stack Exchange & IOTA help pages, here and here.
So I would expect an IOTA foundation member answering a question about potential security flaws to disclose the membership in that answer. On the other hand, it's not necessary when answering about DAGs in general or other answers which are basically public knowledge or the current state of science or technology.
What is totally out of the question is you providing any list about people!
You may comment on single answers where you feel the affiliation would be necessary and where it is missing and you think that person is an IOTA foundation member or other person who should disclose it there. Start with asking if the person is who you think they are. Never forget, that an internet handle used in two places must not necessarily mean there is the same person behind the screen.
If you feel that someone is generally misrepresenting themselves as non-affiliated party and often answering questions where the affiliation according to official guidelines should be part of the answer and commenting doesn't change that you may flag one of the answers for moderator attention. In that case use moderators and if need be in contact with SE staff will look into that matter.