I'm a bit disappointed as it is not the correct spelling of his Alias *I say Alias because Shirow Masamune is not his true name* but if this is danbooru's naming scheme system, well that is that.
:<
jjj14 said: I recommend you familiarize yourself with howto:romanize.
士郎 正宗 (correct romanization: "Shirou Masamune") is his penname. 士郎 is read シ+ロウ via on'yomi, as is common for names, which comes out to "shi rou" (the "u" is present, and influences the length and pronunciation of the vowel sound). The "Shirow" spelling is pretty much just guesswork, not an accurate romanization.
My only confusion on his name was that "Shirou" (or any name ending in 郎, for that matter) is in the style of given names, not family names. Further, the name was not spelled with an equal sign or a dot between the names to signify a Western (given name → last name) order. Thus, in theory at least, the name should have been 正宗 士郎. However, this is the order Shirou has chosen, so...
Honestly, I would prefer to have the whole thing aliased over to oota masanori to fit with his real name of 太田 まさのり.
I think with artists, we should use the name they currently go by on most of their work, rather than their birth name, if both are known and different.
In principle, tags are just codes. If Danbooru had a reason for that, artist tags could be something like aaa1g5t and aab67ht. I wonder if anyone would come here like, "aaa1g5t is incorrect, Masamune Shirow is correct".
The reason for the current romanizations used in tags is that the Danbooru community has been very interested in the Japanese spellings of the names -- especially hiragana (or katakana) spellings, which reveal the correct pronunciations.
Shirou Masamune is correct in the sense that it gives us the desired information on the hiragana spelling of the pen name.
The place to find the correct latinization ("correct" as in what official publications use) is the Danbooru wiki. The wiki should definitely mention the spelling Masamune Shirow or give a link to the English-language Wikipedia for those willing to find it. If the wiki lacks this kind of info for any author, members are free and encouraged to add it.
All this being thought out, it is sufficient to mention once that "Shirou is incorrect". Such things are already known by the staff, especially when it comes to famous artists.