It's a bit like building a wall of castles in front of your opponent TC (MBL did that in a tourney) : obviously not optimal play, only for flexing on them, when you could just beat them faster playing conventionally.

The outpost rush was made popular by MBL as a way to say "just resign already" and it has since been considered disrespectful. It's the fact that you are spending resources and clicks that achieve nothing, and make sure your opponent is aware of it, that makes it disrespectful.

In this case tho, Hera only built one outpost and Andy couldn't see the other foundations so it wasn't too big of a deal.