Learn Portuguese (Portugal): O facto de o tabloide não apurar a informação verídica é péssimo. - The fact that the tabloid doesn't ascertain truthful information is terrible.

In Portuguese, you must never contract a preposition with the article or pronoun that acts as the subject of the following verb. Because o tabloide is the subject of the personal infinitive apurar, the preposition de and the article o must remain strictly separate.

Since apurar looks just like the regular dictionary form of the verb, is it really the personal infinitive here?

Yes, it is the personal infinitive. Even though the third-person singular of the personal infinitive happens to look perfectly identical to the impersonal infinitive, its function here is personal because it has a clearly defined subject (o tabloide). The phrase o facto de is a classic trigger for this personal infinitive structure.

Could I use the subjunctive instead of the personal infinitive to express this?

Yes, you absolutely can. You would use the phrase o facto de que, which triggers the subjunctive, resulting in: O facto de que o tabloide não apure a informação... However, Portuguese speakers very frequently prefer the o facto de + personal infinitive structure used in this sentence because it is considered slightly more concise and elegant.

I haven't seen apurar used like this before. What does it mean exactly in this context?