It's just human nature.
- how and why we exist
- our purpose
- what is good (and who is good)
- what is bad (and who is bad)
- what rules to live by
- how to attain happiness/salvation
Traditional religions provide this for the majority. In their absence, most still seek it.
It's not by accident that most climate alarmists, communists, radical feminists, SJWs, militant vegans, etc. are atheistic.
These are secular religions.