Because that's exactly what they want. An all white maga military to do their bidding without repercussions. Hell a memorandum was just released a few weeks ago stating that anyone who need a shaving waiver over 1 year will be discharged. Guess what demographic usually require a shaving waiver in the us military.
They don't want Black men in the army because that's where military offence and defence is learned..
The fewer Black men in the army learning those combat strategy skills the better for White supremacists in the US to fukk around with Black people and not have those communities with men that have been in the army and fought.