still not a legit reason to go mad, kill people and try to hack the moon and everyone on the earth..I hate simple-mindedness like this. Allow me to enlighten you a bit.
Obito did not just "lose a crush". He loved Rin, she was the only one who gave him any real attention. Then, when he was about to die, the only thing that could give his soul peace was knowing that his closest friend is going to protect her.
Now imagine surviving, the joy you must feel. Then, when you see them again, what's happening? The same person that promised to protect her is the one killing her, his lightning-infused hand piercing her chest and her life fading away rapidly. Obito didn't just "lose a crush", his entire ideal set, his whole concept of what the world was was shattered right before his eyes. What Obito lost is much more than you can even hope to someday have the brainpower to comprehend.
just my opinion.
Compare Obito's situation with Sasuke's.. Sasuke's is alot more reasonable tbh