The only thing that was made clear about his anger or the fact that he was "out of his mind" was that all of it was directed towards Oscorp. They deliberately ousted him by pinning the Max/Electro fiasco on him, and he had a legitimate reason to get back at the company.
Just because he's not in his senses, he decides to take away the "hope" of the one person that wasn't against him in the movie (outside of Felicia and Electro)?
It doesn't add up at all.
But Harry didn’t see Peter’s refusal to help as a good thing. WE, the audience understand Peter’s decision because we’re watching it from the hero’s perspective. But from Harry’s perspective, by flat out refusing to help, Peter is signing Harry’s death note. Peter isn’t even giving Harry a fighting chance. In Harry’s mind, Peter is making Harry’s decision for him, without even attempting to come up with a plan that could work. From Harry’s perspective the situation is:
Harry: I’m dying. The ONLY chance I have is using some of your blood. Help me, please?
Spidey: No. It’s dangerous.
Harry: Isn’t that my choice? I’m already dying…PLEASE!
Spidey: Nope.
Harry: We could run tests to make sure –
Spidey: No.
Harry: I thought you’re supposed to help people?
Spidey: That’s true. I do help people, but I’m not gonna help you.
Harry: Oh my god, I’m gonna die…
Spidey: HA! Sucker!
The ONE person that could possibly help him absolutely refuses to. From Harry’s perspective, that really is a completely dick move. Then to find out the stranger who completely destroyed your own chance to survive (and therefore made the decision to let you die miserably) is your best friend…yeah, NO ONE would take that well at all.
This, of course, completely ignores the back-and-forth love/hate mind**** the goblin serum has on Harry and Norman in the comics.