There are two possible reasons.
Firstly, some very low-quality registry cleaners which give a bad name for the whole industry make up errors in order to scare the user to buy the product.
Secondly, comparing registry cleaners based on the number of errors they find is not relevant. Partly because of point number one, but also because quantity doesn't mean quality. Our products are trusted because they are the safest around, we can have our competitors to find a few more errors every now and then if this means our product fixes computer problems, and won't cause them by improperly detecting valid registry data as errors.
