Why is it bad to Tonemap exterior scenes? Please excuse my ignorance (still trying to wrap my head around this)

First off, I have watched BlenderGuru, CG Cookie and read the BSE threads from TROY_S and others, and followed this comical thread along with going down the "rabbit hole" . I feel I have an ok understanding of this, but certain statements really confuse me. 

In this post, 



the OP says he would not use tonemapping for exterior scenes and keep it Linear? Why not for exterior?

how would you render a scene and keep it Linear without tonemapping? Would this be done by selecting "none" in the filmic looks? 

I thought if you are using "Filmic" from Troy_S you ARE tonemapping while keeping it linear? 

... Sorry the more I learn the more confused I get.
It's not.

Tonemapping is extremely common for exterior scenes, even outside the CG world. Before computers and exposure bracketing, photographers used graduated ND filters as a rudimentary way to tonemap the sky which is usually over-exposed compared to the rest of the landscape.

Tonemapping is an artistic choice, there are no rules for when you can and can't do it.