Not very logical to get full-rated 2 engine go-around thrust, for a normal go-around where you only have to climb a few thousand feet. Not very logical to get 6000 fpm climb rate, not very pax friendly and not so super for congested airspace. Not that clever with regards to pilot workload.
On Boeing, you may have to advance the thrust levers manually (oh god!), if PM monitoring doesn't reach in and arm the auto throttle. Or if SOP permit, you may leave it armed from the get go. There is really nothing to be confused about, if you are a proficient pilot..