If an employee does something actively malicious, you should absolute remove them. This is very rare though - incompetence /broken systems is much more likely.
Otherwise you develop internal process that's entirely scar tissue, and only stops your teams doing their jobs.
I feel it is somewhat obvious and goes without saying that malicious action results in personal responsibility & repercussions. However I don't have any evidence or past experience that malicious action by an internal employee is a likely scenario for most outages. It may well occur but most examples I've heard of seem apocryphal.
The scar tissue: this is where good choices come in because it's certainly not a rule that a change as a result of an incident review is an impediment to work. These definitely occur, and sometimes linger after the root cause is phased out. But best practices often reduce cognitive & process overheads.
A rough example is that there are still people out there FTPing code to servers, having to manually select which files from a directory to upload. Replacing this error prone process with a deployment pipeline leads to a massive reduction in the likelihood of errors and will actually speed up the deployment process. It's all about making the right choices, not knee-jerk protections, and sometimes the choice is to leave things as they are.
Otherwise you develop internal process that's entirely scar tissue, and only stops your teams doing their jobs.