Does people's aversion to non-active-waypoints also cover abeam positions generated by the FMGC?
Not sure about FMGCs but in the case of this Boeing, FMC user abeams are also a "no no" in an ADS environment - for all the reasons previously mentioned ( corrupt ADS position reports).
If abeams are needed the teaching is to display Route 2, the non-active route, on the Navigation Display (ND)- this of course assumes you've copied the original route into Route 2 in the first place
, or use the FMC fix pages and/or waypoint/station function on the ND.