Presumably because they think it's kinda embarrassing to be associated with the quintessential symbol of being humiliated for being fuckwits.
Twitter Link
Expect any bases or the like named after traitorous losers who fought under that flag will retain their current names. An error seems to have slipped past the editors—it says the flag has often been co-opted by violent extremists and racists, when it's clearly supposed say that the flag was created by violent extremists and racists.