There is no problem in itself with close or identical usernames. There is a quite active user quid on money.se that is not me. There are any number of users named John, some of them likely actually named John others just picking it as some common name. And so on.
This was also said in the message: "even identical user names are possible."
The message does not in itself amount to a prohibition of the use of this display-name. As mentioned in comments it is a request for information. Reasons why the question is asked are also suggested in comments.
The situation seemed unclear. Thus, we decided to ask for clarification. Maybe the choice is independent, maybe it is related. If it is related, it could be related in a positive, neutral or negative way.
It's not quite the same if you pick amWily because you admire amWhy's contributions or if instead you pick amWily to spite amWhy.
Or, for something in the middle, noted the name amWhy found it a neat idea and modified it for your purpose not thinking it would cause much issue.
We also can not know in advance if this is very relevant to you. I used an SE site for a quite a long time without particular display name. At some point I was encouraged to pick one to avoid confusions (back in the day there was not even a numbering). So, I came up with quid. Further, had somebody told me back then we prefer you not use quid for some reason, I might just have changed to something else. If you'd want me to change now, that'd be a bit different, but then you just joined.
If it is very important to you to keep the name, we will need to see how to proceed. But if it is not, then maybe you could do us a favor and just pick something else (rather than to insist on your right to pick your displayname) and we all move on.
In advance, we cannot even know if it is important to you whence we started an exchange about the subject.
The issue with the votes is orthogonal. If the votes are due to the usename issue that's not alright even if the usernamme would be found to be problematic. But there are many 'if' there. Better to focus on one subject at a time.