HOWEVER. That being said, I believe there are limitations and safety concerns to consider. Obviously someone shouldn't start out jumping a 3' elevation! But what may be obvious to some might not be to others, and therein lies the actual problem. But for those who have above levels of common sense and actually LEARN on their own, from their mistakes and from watching others and from asking for help - those people, I think are fine on their own.
I do not plan on showing. I simply want to enjoy my horse on a trail, overland, etc. The only training I'd like would be when I just can't get it right. I took lessons years ago for riding and TBH, the fundamentals of those lessons have never left (and shows when I am riding in a saddle too small for me, get jostled and tossed about and immediately revert to posting to help position myself better - all in a western saddle!)
If I take Chili out on a trail and jump a small creek or log, am I going to endanger her or myself? It's possible. Would the danger be limited if I were trained to jump her over said creek or log? Perhaps or perhaps not. I personally would never force my horse to do anything - especially jumping. If we happen upon something and she feels the need to rabbit over it, by all means, I'm going to let her. However, if she refuses to STEP over, I'll walk her around or find another route. But that's just me. I'm not going to endanger my horse or myself. I think that is the difference between people who should be teaching themselves and those who **** well should not be!
*I edited your post just to emphasize what I am replying to*
I agree very much to what you just said, thank you.
It all depends on the person, what they are doing, how they are doing it, etc. If a person has previous knowledge of the subject, whether from reading about jumping safety (for example) and has an understanding for it, they would be the person I would most likely let slide.
In my opinion, comments like "you should have a trainer help you with that" are blanket statements. Of course it is different if you're just hopping over a log with your horse on a trail, but jumping your horse and taking pictures and posting them on a public forum, we assume that the rider wants to pursue some sort of jumping with their horse, therefore we encourage them to learn correctly. I don't know what thread you are talking about, I am assuming it is a training or critique thread? Of course it would be different if the rider posted a video of a CTR with a small log and then got bashed because they jumped it. Anyway, I think we have a pretty good understanding here. :)
I will admit that sometimes people can get heated and start to bash. Things can escalate and get nasty. For the most part however, this forum is quick to give good advice and eager to help new riders start out on the right foot :)
ETA: Sorry if I just contradicted myself or am rambling (its a common issue for me), or just made absolutely no sense in some places! It's 2 am and difficult to think soberly. Cheers! :)