I agree that this looks like an inconsistency.
No matter how you want to classify the sentences, they have the same grammatical structure.
- Give me blood.
- Be industrious.
- I will give you freedom.
- You will succeed in life.
You can assume that the first clauses are implied conditionals, and therefore subordinate, but there's no reason to assume that only one of them behaves that way.
The only actual difference I can see, which doesn't change the essential analysis, is that to make the second version conditional you would also likely change the conjugation of its verb:
- If you give me blood
and, then I will give you freedom.
- If you
be are industrious and, then you will succeed at life.
Note that if you be industrious is actually grammatical, so it doesn't really have to be changed. However, that type of language isn't what most people would use in modern English.
Note, too, that once they become (or are assumed to be) conditional, they are no longer imperative.
But since both sentences have to have changes made to them anyway in order to have a conditional explicitly expressed, I don't see why changing a verb conjugation in the second sentence should make a difference.
If you're assuming an implied conditional in the one, you can also assume an implied conditional in the other.
It might be possible to interpret each sentence in two different ways (even if one of the interpretations is wrong), and it could be they are interpreting one in one way and the other in the other way. But, if so, they have not stated that.
To give only one interpretation to the first sentence and a different interpretation to the other sentence is either inconsistent or misleading.