It's not as simple as the article suggests. The FBI isn't a single unified group, it's split into several branches, each of which has multiple divisions, then individuals are spread out across different offices.
The pro-Trump atmosphere is more pervasive in New York and DC, and Islamophobia is a bigger problem in the counterterrorism division. Elsewhere things are more moderate.
The Trump/Russia stuff has been a counterintelligence investigation, and those people don't play favorites.