Yes, they would be considered hybrids. I'm not going to get into ethics of hybrids, but I'll give you the facts. There aren't three 'types' of blood pythons; there are three
species of short-tail python,
P. brongersmai (blood),
P. breitensteini (Borneo short tail), and
P. curtus (Sumatran short tail). They are completely different species, so yes, a cross between, say, a blood and a Sumatran short-tail, would be a hybrid.
I've seen plenty of short-tail crosses, especially between bloods and Borneos. I don't believe they can reproduce amongst themselves. Now, whether it's morally right is up to you. I believe there are already a few threads on the ethics of it.