I don’t know that much about materials science. Why is a “titanium hemisphere bonded to a carbon fiber cylinder” “such a fundamentally compromised design” in th

I don’t know that much about materials science. Why is a “titanium hemisphere bonded to a carbon fiber cylinder” “such a fundamentally compromised design” in this application? I imagine maybe carbon fiber would be better in tension (e.g. airframes) than in compression (this), perhaps. Or do carbon fiber and titanium not get along somehow? (EDIT: Had tension and compression backwards.)