I can tell you that at the Coast Guard Academy there seems to be politics. I got in to USAFA and many other excellent civilian schools and am waiting on USNA but got waitlist on CGA?? Go figuire! I had no weakness on my application: 1 B in highschool the rest were A s, 4.2 GPA. 32 ACT composite, excellent CFA and tons of ECAs.
Remember that USCGA does not require Noms so you are competing against a national pool with a very small class size. One thing to look at is what classes you took, did you take all APs and a lot of STEM classes? I know kids with 3 or 4 B's and a 4.2 to 4.3 GPA. I am not trying to put you down, your stats are very good and you have worked hard, but I don't think it is fair to claim USCGA or any other SA is playing politics without proof.