AWS network inbound rules: All traffic is no traffic

I found a very weird problem in AWS' network inbound rules, that although the default rule is to allow all traffic, it actually allows no traffic. At least is the case for PostgreSQL's port 5432 and SSH's port 22. 

To fix, I had to manually add rules to allow inbound traffic to certain ports, like below:

This sounds redundant but I had to do this to make it work. 

I could set the source in the first rule to 0.0.0.0/0. This was the error I got: 

If you have an explanation, please feel free to let me know.