In his opinion, the medical profession is being bought by the pharmaceutical industry. This doesn't make it true

In your opinion he's speaking about his opinion. In reality he stated that the medical profession is being bought by the pharmaceutical industry, and to you, in your opinion that automatically makes it a statement of opinion.

By your logic, you'd consider it fact if someone was to say "Lucy bought a candybar at the store today," when in reality Lucy may not have even left the house.

You can make a false statement of facts, but that doesn't make it opinion, opinion is a motive or reason, not an observation, something that cannot be demonstrated, where as saying that so and so bought this can be, so automatically ruling it out as opinion is no sense, or lie, considering the credentials

He's arguing his position, it's his belief, it's his opinion. Other people will say "No the medical profession isn't being bought by the pharmaceutical industry."

Yeah, it makes sense, he is just debating whether or not the people that pay for the studies and give the grants to the universities are actually controlling what the scientists study or not. And right there he just unequivocally closed a point, which you say is an opinion in the real context. We will just have to take your word for it again, that it's not a statement of fact when you say I did this" it's an opinion.