Not that the kick itself is wrong, but the application. I admit to not training Muay Thai, and hence never using a shin kick, but my impression is that you should be rather careful with how you employ it because, yes, if you meet an opposing shin square on while going all out, you're likely to break something. So, I might suggest being more reserved and careful in how you employ it, in much the same way that people who train to strike without gloves are much more reserved and careful about smashing their knuckles into potentially hard, boney targets.
Open hand strikes exist for a great reason, just like other forms of kicks exist for a great reason. My suggestion is to train with an awareness of what happens when you take off the protective gear, and how you need to change your behavior when you do, so that you think twice about throwing, say, a shin kick with all your might at an angle that your opponent can check it square on.
Even Mike Tyson broke his hand when he got into a fight outside of the ring, and wasn't wearing gloves. That didn't have to happen. It's just that he never trained for a situation where he might not be wearing wraps and gloves.
Training to turn your limbs into specialized, armored bludgeoning devices comes with some drawbacks, and artificially warps the nature of what you do in competition versus reality. The more you add artificial elements, the more you start to play a game that has less and less similarity to what it's supposed to. Fewer rules, and less protective equipment, is exactly why MMA / UFC became popular in the first place.
See my sword/stick fighting analogy at the end of page 1.