I would say that’s a rather cynical way to view the world (others would say it’s just a factual perspective). But if you view this scenario from that perspective, there’s no logical reason that you shouldn’t also view the relationships you have with your own spouse/parents/children/friends... the same way.
With a corporation or politician? Not so much.
However whether reciprocity was involved doesn’t at all change the existence of a self-interested motive. It’s simply irrelevant.
Furthermore, in this case there was reciprocity. In this instance the big corporate interests were selling a product for which doctors had a demand to treat their patients. You’re welcome to have an opinion about the integrity and value of that reciprocity, but that goes for anybody in regards to any relationship. A cynical person could come to that conclusion about any relationship, and offer you a justification for it supported entirely by a leading thesis from the field of ethics.
Absolutely. And while such attitudes are not incredibly widespread, there are enough folks who do so that we have a name for exhibiting such behavior. We call it Narcissistic Personality Disorder[0].
Which is a terrible thing to do of course, as it stigmatizes a whole group of people that just want to live their lives and use the the objects in their environment to their advantage. What's bad with that?
[0] https://www.helpguide.org/articles/mental-disorders/narcissi...
People have debated for a very long time whether a person who derives satisfaction from benefitting others is truely motivated by the benefit of others, or simply the benefit of themselves by way of that satisfaction. A narcissist is a completely different thing. They would not derive satisfaction from benefitting others, for reasons such as their narcissistic lack of empathy.