Unethical according to whom and to what rule? Unethical according to what religion or commandment?
This site is a type of 'reaction-site' where people discuss people in real terms, not in symbols and not with, necessarily, hidden information. Matt's dad is NOT the only one mentioned on this site, and others have provided the names of his aunts, cousins, and others, including identifying information for them and also for her previous boyfriend, Tiroy Nicholas, who is a successful engineer as per his Linked in profile. Others have even provided the date of birth of Geoff Ferris. (For those who have been here for lots and lots of time, remember when Geoff's Ferris' date of birth was provided in earlier threads in order to figure out if it would be logical based on birth dates that he could be Matt's dad?!)
This information is readily available online, as are Tiffany's financials related to a loan that she never repaid because she liquidated her business. Someone even provided the links and/or the documents themselves in these threads! As far as information is concerned, as long as it is available freely on the internet for all to see and download, it is fair game to be discussed on this site, and on others as well.
You are correct that it was the name of the current business that Tiffany didn't know.
You wrote "It isn't necessary to look for a negative connotation in every single remark, nor is it necessary to dox Matt's family."
These threads by their very existence aren't 'necessary', and nor are Tiffany's videos. If you think mentioning real names isn't necessary, feel free not to mention them. By her own doing through her videos, Tiffany Maurice-Christy (Yes, this is her full name, and it is publicly available.) is now a public figure earning thousands of pounds every month from her videos. Anonymity is what one trades for such income in the public sphere. Call this mention of real names what you will, it is fully legal to do so with the information being freely available on the internet.