There was no good old days with Christianity. Christianity engaged in evil from day one. It set back Europe a thousand years when the buried many of brilliant ideas of antiquity because it interfered with their mythology. Europe only started to heal as Christianity lost power post Renaissance. The US forefathers although Christians to their credit had the wisdom to separate Church and state in the US. They recognized the threat to reason and freedom posed by religious fanaticism.
It’s not even entirely clear if Jesus even existed. There is virtually no evidence of his existence from his era outside of religious sources. What seems to have happened is those that wrote the bible were either conscious con men or were passed on embellished folklore stores of events that never happened. It’s always the same story with sundry religions with supreme beings. Their entities can create an entire universe but always go into hiding when someone asks for evidence of their existence.