This topic in one form or another is a perennial chestnut! I make the following observations:
Anyone who uses a JPEG straight from the camera is using post processing. The post processing of the camera is very extensive to take the RAW data and turn it into a JPEG. That post processing is pre-conditioned by choices the photographer made - picture style, colour balance, exposure compensation to name a few. Similarly the moment someone just crops, straightens, or changes brightness (exposure) they too are post processing. Perhaps the least in-camera modified is from a smart phone?
More seriously though, there are many genres of imagery. It would be unforgivable for a photojournalist to deliberately modify an image to mislead the viewer. Similarly a Documentary photographer is surely bound to show as best s/he can the truth of the subject matter they are trying to convey.
But a fine art photographer - be it landscape or fashion or whatever, is free to portray as best they can, using whatever tools at their disposal, what they experienced or is trying to show. In that, they are no diffierent from a painter, its just there toolkit is a camera instead of a brush and paint. Adams is a past master with film. David Bailey, one of the most successful fashion photographers of recent times, seems to turn his hand to any genre and meium with ease, and has said something like he would have been just as happy to use brush and canvas but that it took too long to dry.
In our own way, some of us want to be journalists or to document what we see, others aspire to fine art to convey a mood or emotions. And many just want snapshots of events as reminders of a great day out/ party/ trip to the lake or whatver. None is right or wrong. Decide what you want and go for it is what I say.
I wish I was good enough to be fine art photographer, not for money but just so others enjoy some of my images like I do. Much of my photography is by my own definition, snapshots and is post processed with Fastone viewer for crop, shadow and highlight exposure, straightening etc in a few seconds. Every now and then I get a good one which deserves a lot more attention to turn it into something I want to hang on a wall as in this example from Bryce Canyon. Most of my photos look almost identical to tens of thousands of others and a a personal reminder of a great day out. As I was walking back to the car after the sun set carrying the tripod with camera still attached, I glanced to the left, immediately set up the tripod and took this shot. Less than a minute later, once I had 4 or 5 in the bag, I then positioned to better frame etc and the moment and light was gone. This one image had more photo-shopping than the rest from that day together: layering and masking to isolate and change exposure and contrast of the tree; masking to increase contrast and vibrance in the sky; some spot dodging; cropping, straightening; some cloning to remove litter left by another visitor etc. About the only thing not touched was colour balance and overall exposure. I ended up with an image which as near as I can remember is what I saw and experienced.
If you like it then great, if not, never mind. if it's too processed for your taste I don't care