Criminal Defense Attorneys as GALs

I have noticed a trend of criminal defense attorneys accepting roles as GALs (guardian ad litems).  From what I have seen they are good about not accepting assignments when there is a clear conflict of interest.  But I don't see how it is possible to let the mindset you gain when working with criminal defendants not color your decisions as a GAL in family court, especially considering that GALs are most often appointed on cases where there is domestic violence and so the children are at a minimum secondary victims.  How can someone switch back and forth between two vastly different sides without letting the work they do on the other side color their work?