I don't think your Molly recording is all that distorted.
I am assuming that the stacks at the Molly stage were on the far sides, or up above you.
Which means you weren't getting any of the sound from the stacks
Most of the instruments you are picking up are the monitor feeds that the band listen to.
The main purpose of the monitors is so that the band can hear what they are playing.
They are nice and amplified, so they can also be heard by those in the front rows.
But the vocals are usually sent to an in-ear monitor as most singers are all over the stage.
The problem is, in your location, the vocals are muddy at best. As the vocals aren't usually prominent in the musician's monitors. They want to hear the instrument 'they' are playing.
With the other group. With it being bigger, and more bombastic, I'll bet they had some stacks towards the back of the stage as well. So those in the front, on the floor, in the pit, etc, can hear everything.
This is one of the reasons, that a lot of people think opening acts get a crappier mix than the headliners at shows. Sure, sometimes that is true. But a lot of the time, it is because the opening act doesn't have the amount of gear as the headliner. So with only part of the amps or stacks, they can't fill the room with sound like the headliner can.
I've been to shows where you couldn't hear any vocals at all for the opening act if you were in the pit.
There just weren't any sources for the sound to come from.
10 or 12 rows back you could hear them just fine. But close to the stage, there was nothing at all.