It sounds like you are saying, "As long as you use good judgement, nothing bad will happen"
I don't think that is quite true, but suppose it is. And then suppose that I do TGUs five days a week for the next year. What are the chances that I have good judgement for 2500 reps?
I plan on continuing strength training for the next 25 years. I'm going to make mental errors. Some days, I'll be distracted and tired, and not appropriately evaluating my ability to complete a rep. When my days of bad judgment come, guess what, I won't be in the middle of a TGU, surprised by a kettlebell looking to fall through my head or chest. Because I don't do TGUs anymore -- they don't provide anything that I can't get with less risk.
Also, keep in mind that Simple & Sinister is often encouraged to people inexperienced with training, not having developed good judgement about risks in this context. Telling a beginner: "Do this 14 step exercise, and do it correctly -- if you make a mistake and break something, you didn't do it right" is completely unfair. Why not develop strength (and judgment) with safer exercises, and introducing the TGU for those that have accomplished a standard of strength? Seems better than making the TGU up to 32kg the standard "Do this first".
Hmmm... It didn't really seem dangerous to me doing the TGUs with the first level bell of only 16kg. It really didn't seem dangerous at all. Instead, it felt like an adventure in movement. I like the analogy of it to a Karate kata.
I don't think we can escape some measure of risk entirely when lifting weights, unless maybe we're talking about weight machines. By choosing a kettlebell as one's tool over weight machines or bodyweight, we're already taking a bigger risk than with those other ones. Having said all this, my only real injury lifting weights of any serious nature was done doing a bodyweight-only exercise believe it or not! When in doubt use a light kettlebell for the TGUs!
Sure, there are safer ways to train with a kettlebell, but I think there is a tradeoff. I find myself doing a lot of Clean and Press with a kettlebell these days instead of my normal S&S routine, but I'm definitely NOT in as good shape as I was when my S&S was more regular! The TGU and the Swing are bigger movements covering more muscles, more moving parts, more cardio than the C&P, for example. C&P however is more compact and safer I think than those other moves.
There are a lot of alternative workouts presented on this website. One interesting one is of using just the double Clean and Press as one's single move to stay in shape, another one is about just using the Snatch (and some good time spent walking outside too). The basic 6 moves are taught for a reason and there is a "The Works" programme for them as well as "Complexes" involving strings of several moves.
Why something (a bit harder than one might expect) like S&S might be chosen as the go-to program for beginners and even for more experienced people makes sense to me coming from a judo and kendo perspective. It's fine to start out learning things that are "okay" and you can get your exercise etc with, but doing things that work faster and develop your skills quicker, better, and make you stronger more quickly, might be harder to do and involve more precautions, but are worth it since you're doing "the right thing".
We're limiting ourselves to kettlebells in the basic concept underlining S&S (and some other kettlebell based programmes), so given that the tool is going to be a kettlebell, what are the best things to do with it and how? One answer is S&S, and there are others of course, but S&S seems like it promotes a pretty steep learning and strength curve! The movements are indeed hard and challenging, but at least there are only 2 to master! We could start with easier things but then get stronger and more skillful with the tool more slowly.
The kettlebell is a compromise. If used in a way to make it "better" than other kinds of training, then it's things like the TGU and the swing that stand out the most. Clean and Press is better done with a barbell, of course, since you can load more weight onto yourself more conveniently, same for squats, same for cleans. Kettlebells can be seen to have an ergonomic aspect to them in regards to some movements like the TGU and presses, but it's really the Swing where they shine the most - power can be developed quite effectively with kettlebell swings in way that it doesn't seem so convenient with other tools. The rack position is quite ergonomic with a kettlebell.
Basically, the kettlebell is great for asymmetrical, chaotic strength and endurance. For absolute strength it absolutely isn't! To get the most "chaos" and "asymmetry" we go for moves like the Swings and the TGU. The TGU is an asymmetrical and "chaotic" move par excellence! If we're not interested in the kettlebell for this kind of strength I don't see why one would stick with kettlebells, maybe just the swings only, I don't know.
But in any case it's the asymmetry and the chaotic nature of the strength we can develop with S&S that makes it so great, and makes it better than a lot of other things we/I do or can do with this tool.