Interpretation of a hadith about man who emancipated six of his slaves at the time of his death?

I came across this hadith and I want to know the interpretation of this hadith from the scholars, why was the prophet Muhammad (saw) upset with the man emancipated six slaves upon his death and keeping some of them in slavery? > Imran b. Husain reported that a person who had no other property emancipated six slaves of his at the time of his death. Allah's Messenger (ﷺ) called for them and divided them into three sections, cast lots amongst them, and set two free and kept four in slavery; and he (the Holy Prophet) spoke severely of him. https://sunnah.com/muslim/27/83