Attack move to destroy buildings?

You can issue a command queue with SHIFT so they go from one target to the next.

Apart from that, yes this is a strategy game, there will be micro

 

Unless the base is full of un-upgraded towers, its more effective to focus fire units first as a cost/hp thing, and for reducing the damage you're going to take. Most people's complaints about a-moving are that the units tag the first thing they can. Including buildings and walls.

Ideally you probably want to move command (or a move) to the point of the fight and stop command rather than a laissez-faire a-move, because it automatically splits targetting up so there's no overkill (and even still, the units wont automatically prioritize what they counter, and that's where player micro steps in)

 

There's a lot of units that have a priority list. Some of them are broken (Siege ships prioritise units...), but others are designed just for what you want. I can only recommend you bring along a few rams who will prioritise buildings.