The reason I want to have the existing description changed is because it presents an ethical violation for my client.
Note that how someone else describes your client is really beyond you and your client's control and so, having attempted to get it changed, neither you or your client can be held liable.
The term "specializing" cannot be used to describe their practice.
The term "specializing" may have specific meaning for various professions (e.g. medical) and may have implications as a result but the directory usually uses the term generally to indicate specific areas of interest.
In general, there can be a problem with industry specific 'jargon', which editors will try to get right when the terms are unique to an industry
and would be meaningful. Since the directory is geared to the average surfer, it would be difficult to reserve a term like "specializing" (or
"specialising" as I prefer to spell it) to a particular use. (Note it is also why acronyms are discouraged as we bear in mind that the first language of many of our visitors may not be English).
If your update suggestion said something like "can you use the word 'concentrating' in the description instead of 'specializing' as here 'specializing' implies we are certified by xxx/provide xxx services, which we are/do not" then it will be clear to the editor exactly what you want changed and why. Since the editor will be looking to have an accurate and meaningful description, they may or may not agree, but at least they will be addressing your precise point.
regards