As I said above, I find the running of informants at the Academy distasteful, even if I can't articulate why. However, thus far I haven't found anyone--to include Thomas--that I can feel sorry for.
There is a longer thread about it on baseops where a few cadets have posted. One thing you'll notice is that no one says anything about how he got a raw deal.
I know a lot of cadets who were angry to discover there were informants among them. I have yet to meet one who knew him that thinks Thomas got kicked out for anything but what he deserved.