Well, that too, but getting anger out is also a big part of it.

[Like when those humans on TV punch those giant cylinder bag things. Or at least, that's what he's pretty sure that's what they're for...

And that pose is indeed familiar, so time to distract with some questioning!]

Well, that's...

What would be the other choice?

You obviously need to drink blood. I don't know what you'd do without it, but you'd at least starve. Some blood was being provided. At that point, it seems like you had to either take it, or risk someone-someone we know getting hurt.

And...at that point, I think that's only one option.