Splash dmg through the bubble is a bug. And it’s still not enough to compete against a naked man with a repair hammer. That said u even need a surface to apply dmg to in order to deal splash dmg through the bubble. If you build in a high pillar there is no way to use it even.
That people are content with pillar bases shows a certain resignation that the community silently agrees to using exploits in order to play the game 
If I see tips on how to raid a pillar base I haven’t seen one advice that is involving a legitimate way to deal dmg or not relying on stupid owners of that base.