Sorry that this has affected you so negatively, but I’m glad it’s out in the open and we can deal with it and get more of your photography.
For me, cropping for wildlife comes down to one thing - detail. If you have crisp, “tack-sharp” focus where you want it, I think cropping to show that will serve the photo. If you don’t, but it’s close enough and everything else is good, an environmental presentation will serve. Here are two shots to illustrate what I mean -
Same lens, a 70-200 equivalent, but obviously the distance to subject was different. So without the detail in the second shot, I have no business trying to crop it to fill the frame. An extreme example, I know, but you see what I mean. In the first, it’s a bit of a crop, but really only to make it square. It holds up, but is also showing the bird’s habitat (Caddo Lake, Texas).
I think for tiny creatures it’s even harder to manage. Unless you’re standing on them, they’re going to be small in the frame. If you’re out doing wildlife photography, I have to assume showing the critter is your goal. A massive environmental shot of a tiny creature might not be doing that creature justice if you’ve got everything right including focus. So crop to serve the animal.
Also crop to serve you and your vision. In your photo here I think you have a bit too much environment for a portrait, which this clearly is. If you were trying to illustrate how small chipmunks are in relation to the rest of the world, it’s not wide enough. It looks accidental. My opinion only, so take it for what you will.
Stick to your guns if you think it serves your purpose, vision and subject. Crop to reinforce the strengths of the photo. Sometimes I’ll back off my zoom so that I can have more choice in that matter. Check out my discussion here for some similar chipmunk shots - Animal detection - #4 by Kris_Smith They’re all crops, but of varying degrees…the middle one was to illustrate the intervening undergrowth that’s mostly out of focus.
It’s taken me a long time to develop a thick enough skin about my work to take criticism. It is still sometimes hard, but I try to distance my emotions from the end result. Nature and maybe portrait photography are the most emotional types of work for the photographer, at least in my experience and so we may be setting up ourselves for a bit of a battering when it comes to critique, but in the end it will make us better if we pay attention and remember new lessons.
Ok. I’ll shut up now.