A turing complete program could, by definition, generate any other turing complete program. In theory, you can statically analyse any program to prove that it

A turing complete program could, by definition, generate any other turing complete program. In theory, you can statically analyse any program to prove that it doesn't contain malicious code (for some definition of malicious). But if a program is turing complete, you cannot predict all of its possible outputs and therefore, cannot rule out the possibility of a malicious output. The halting problem is what prevents you doing the analysis, not what introduces the possibility of maliciousness.