> The Obama administration was pro-monopolist basically across the board for eight straight years.

It might be more accurate to say that rubber-stamping mergers maxed-out under the Obama DoJ.

    Comcast - NBCUniversal (2011)
    
    AT&T - T-Mobile (2011)
    
    Express Scripts - Medco Health Solutions (2012)
    
    Google - Motorola Mobility (2012)
    
    Anheuser-Busch InBev - Grupo Modelo (2013)
    
    US Airways - American Airlines (2013)
    
    Oracle - Sun Microsystems (2010)
    
    Comcast - Time Warner Cable (2014)
    
    Heinz - Kraft Foods (2015)
    
    AT&T - DirecTV (2015)

Administrations before and after were almost-but-maybe-a-tiny-bit-less eager to approve competition+job killing mergers.

What DoJs were not eager to do was push back against pressure from Elected Congresspeople who 1) held DoJ purse strings and 2) had elections that needed funding.

Yup. We are in our current predicament because the previous 4 or 5 administrations, whether D or R, have let corporations run amok with M&A and general anticompetitive behavior, offering only token resistance. Biden has finally signaled a shift in the last year or two, but it remains to be seen how far these actions will go (and how much Congress and the courts will allow).