Should Biden's Justice Department support Trump in his defamation lawsuit?

I don't approve of the Justice Department defending Trump in E. Jean Carroll's defamation lawsuit. While Trump was President, he denied her claims of an incident in a dressing room and called her a liar and denied ever meeting her. The Trump Justice Department was trying to replace Trump as the defendant in order to eliminate the President's legal liability and the Biden Justice Department is continuing with this approach.

https://abcnews.go.com/US/judges-reluctant-trump-acting-president-allegedly-defamed-jean/story?id=96339956

It would certainly be appropriate for Trump to deny the allegations or to not remember them. Trump actually attacked her by calling her a liar and denied ever meeting her. I assert that the Justice Department should only defend Trump for his actions related to official government duties BUT the E. Jean Carroll is a purely personal legal matter. She does have a rape case against him and she claims to have the original dress with DNA evidence.

https://www.npr.org/2023/01/13/1149124488/e-jean-carroll-rape-claim-donald-trump