Having an engine go to idle would be a good thing at that time,(except for a critical phase of flight) so the starter had something to drive, hence provide some drag on the starter and maybe prevent a starter from blowing up.
If you have seen the damage a starter can do after coming apart to an engine and accessories and cowlings, its quite remarkable.
The only reason you would go to ground start in the air, is the need for an inflight start and you were below 250 knots.(or so)
And, you have to physically hold the switch in the grd. start position as it is not a lever lock position.
Some folks just like to play with too many things!