instead it creates a condition: return, THEN destroy
Does it?
How did you know that it was some kind of a condition?
In general, Magic is a game that works based on rules. You do get a free pass on this one because the rules are nowhere to be found in client. However,
101.3. Any part of an instruction that’s impossible to perform is ignored. (In many cases the card will specify consequences for this; if it doesn’t, there’s no effect.)
The parts of its effect that cannot be performed are simply ignored without any consequence to the spell's resolution.