If you use the correct technique and bring the aircraft almost to a stop and then release the brakes and let the aircraft accelerate and then repeat the process this will keep the brakes cool.
While I appreciate that this is the only technique that leads to a low average taxi speed without overheating the brakes, I can also imagine that the passengers don't really enjoy this endless accellerate/brake cycle. Let alone the cabin crew trying to do the safety brief at that time.
I can imagine it's much more comfortable for everybody involved just to let the aircraft taxi at whatever speed the idle thrust delivers. Until that speed is too high for whatever turn you need to make, or confined area you need to enter, at which point you brake.
So I can understand the frustration of the Airbus crew when they ended up behind a slow GA plane. That they vented it via the radio is perhaps a bit unprofessional, but their frustration, IMO, is justified. Was there really no intersection that you could have entered to let them pass, or something like that?
"Never taxi an aircraft faster than a man can walk"
Apparently a lot of pilots don't think like that at all. Otherwise this NOTAM would not have been necessary:
EHRD(ROTTERDAM/ROTTERDAM)
AGA B)01 AUG 2011 08:59 UTC C)PERM (A0770/11)
E) CAUTION ADVISED DURING TAXIING ON APRONS, INCLUDING TWY N AND Y.
MAX SPEED 15KT.
On a related note, are there any official/legal guidelines as to taxi speed limits? Walking pace is obviously too slow if you have to taxi along a 3km runway, down a straight taxiway with no intersections. But on the other hand, at Tempelhof I've had to follow a follow-me car straight across the apron at Vs or thereabouts. Makes you pay attention to stick positions...
