Hello, this is a frequently recurring question that you can find the full answer to here.
Mojang intended previous usernames to be seen. NameMC's website is meant to be a reference tool with the goal of having the most complete and accurate name information possible. Therefore, we will not remove any name information from the website, and any requests to have your previous usernames removed will be ignored.
The only exception to this is if your username contained your FULL name, not only your first or last. If this is the case you should contact a staff member either on here or on our Discord and we might be able to help you.
Your question had been answered,