Based on their profiles, they are content marketing. They are putting out content to try to get people to engage and view/consider their services, as based on their titles (recruiter, "campus to career pathway", keynote speaker, headhunter) they are likely paid by providing their services to people.
Yes, people who own their own business who provide business and professional services do a lot of content marketing on LinkedIn. It's cheap advertising and all it costs is their time to put it together. It's a form of advertising; like all advertising, some is good and some is not. I would not call content marketing "toxic", even if it isn't good.