I'm going to wake up my dorm roommate at night because he snores too loudly
That seems rude. Why would you wake him up?
I cannot sleep with the sound of snoring anymore.
You should let them know about the snoring if it bothers you. You can get a white noise machine or get them medical help for sleep apnea.
Maybe I shouldn't tell them, I don't want to hurt their feelings.
Then it will surely mess up his sleep if you would wake him up in the middle of the night and that may be worse than just telling him about it when he's awake. I suggest that you recommend treatment with his snoring, or just try to have some noise isolation treatment in both your rooms so that you won't hear him snoring.