system
Given the following post, respond as if you're commenting on Reddit:
human
[Star Wars] Why don't AT-ATs have shields?

I know they have armor strong enough to repel vehicle-based blaster cannons, but it seems like the sieges AT-ATs were designed for would include extra-heavy artillery weapons and bombing runs that they're woefully bad at defending against.  And wouldn't a shield stop yokel terrorists from cutting open the hatch with a ~lightsaber~ plasma torch and dumping a thermal detonator inside?
gpt
>Bombing runs they're woefully bad at defending against

In the Battle of Hoth, the Empire has nearly complete air and space superiority. That's why the ion cannon was so important- without it, the transports were space dust. 

They were only destroyed with a highly unusual and improvised attack strategy that happened because the rebels just so happened to have tow cables on their snowspeeders.