Hyperpartisanship in the IC and LE

With regard to the IC, consider John Brennan's opinion of Trump 45 expressed here: 

https://thehill.com/policy/defense/527339-brennan-takes-final-shot-at-trump-i-leave-his-fate-to-our-judicial-system-his

Sure, that view is expressed four years after Brennan left his position as director of the CIA, but it reveals his post-directorship views on who Trump is and what he accompanied.

Compare my view on Trump:

The man has been grotesquely and unfairly attacked during both his 2016 campaign and, most especially, his term as president.

Why?

Because his agenda was in many ways my agenda, not John Brennan's.

One must note that three of the principals who ran the investigation of Trump in 2016 and into 2017 (John Brennan, James Comey, and Andrew McCabe) have since 2017 revealed their intense and public anti-Trump partisanship.

Did this intense hostility towards Trump only develop after they left their positions of power in the IC and LE?

Or was it developing while they still held leadership positions in the IC and LE, 

and at some level influence and affect their decisions regarding investigations into both Trump and his then-rival Hillary Clinton?

One thing we do know:

Trump was telegraphing back in 2016 the direction in which he hoped to take the country, which led to his election, and which he has largely accomplished.

If now Brennan, Comey, and McCabe pillory that direction, did that hostility to that direction not play a determinative role in their 2016 and 2017 decision-making?

I.e.: They may have been professionals, but were they partisan professionals?