I'm going to tell my friends they're lazy for not donating blood
Why would not donating blood make someone lazy?
It's good for you and it really saves lives. That's why.
You are right about that, but not everyone needs to or can be a blood donor. There are plenty of people out there doing it. You cannot tell your friends what to do.
Maybe I should hire a blood donor for myself, if it really benefits me.
If you want to do that for yourself, that is fine. But let your friends live their lives as they want as well. Don't force anything on them.