That's all levels of awful. I'm so disgusted on your behalf!! Huge congratulations to your son.
Son's HS did their ceremony today. I'll vent a bit here but they do it for D1 and D2 committed athletes, with a separate event for D3 because "they don't sign a NLI" IMO this is crappy and you don't know if the D1 or D2 athletes are signing NLIs. Anyone that's playing at any level in college has put in a ton of work to get there and they should all be celebrated together in my opinion.
First, congratulations to your son and best of luck.
We have 2 public high schools in my town. One never included D3s in the past in November and only included D1s and D2s. This year, at the urging of the baseball coach, they included D3s. The other school had D1s, D2s and D3s this year. But, I think they might have had all for photos outside the school and only had the D1s and D2s sitting at a table signing.
I think the logic of excluding the D3s is because there is no athletic scholarship involved.