Let me just rephrase that question: „Why don‘t you do anything to prevent this glitch?“

The easiest way for this to stop happening is for people to stop designing creatures with unconnected body parts. That‘s the answer to the problem and there is really not much more to it. You don‘t win anything by „exploiting“ the glitch, there are no achievements so there is really no reason why you do would continue to design creatures like that.

Anything I could do would just be too much work and time spent on this non-issue on my part. I don‘t have much time to spend on this project to begin with, so if I do, I want that to be as productive as possible.

If you‘re interested, here‘s why limiting the length of the muscles does not work as easily as you might think:

Do I add a hard limit to the muscles, or do I make it gradually harder for them to expand (on top of the current spring behaviour)? Both options would potentially change the existing behaviour of saved creatures.

What do I set the maximum muscle length to be? If I make it too long, it would be pointless anyway but setting it too short could again break existing creatures.

None of these options are great and all of them would require a significant amount of additional time spent testing.