I tend to agree.
The general practice is for image credits to be provided. The exception would be advertising where that is specifically excluded - and even then credit is often provided.
If the person is marketing photography or related businesses, images from others could be considered fraudulent. If the person is not marketing photography, you would hope the images are appropriately licensed. I still think credit should be given.
Stock photos are available very inexpensively. There is simply no reason for unauthorized use of photos.