How come Xfinity and Comcast discriminate agaisnt US veterans?
Not sure specifically what you are referring to. As a member of a veteran family, Comcast has been nothing but good to us. Your concerns seem to reflect either a lack of understanding about programs available to veteran customers or some kind of misunderstanding. As mentioned by user @jav6joev, maybe you can provide specific details as to what you experienced that led you to author that statement.
For your information, you can learn more about how Comcast is going out of their way to support veterans and their families here: https://forums.xfinity.com/t5/My-Account/ANSWERED-Xfinity-Military-Rewards/ta-p/3225436