Any AWS user can create a community AMI by making it public and shared with everyone. So the answer is just about anyone could have created that community AMI.
While many are probably fine, you cannot trust them by default, in my opinion.
Regarding the specific creator of the AMI in question, it appears that the only user-specific information available is the OwnerId field, which is the AWS account ID of the image owner.
Here’s an example AWS Cli command to get that information:
aws ec2 describe-images --image-ids ami-gs5mba4yp26bsyx57
(Replace “gs5mba4yp26bsyx57” with the ami id you want to examine.)
This will return a lot of information about the image, including the OwnerId field.