This is about how Meklord monsters are summoned. They say "When a face-up monster you control is destroyed by a card effect" in their text. The answer is this:
Unless it specifically tells you that exactly 1 monster must be destroyed, it's usually safe to assume that it doesn't have to be exactly 1 as long as it is at least 1.
Unless it specifically tells you that exactly 1 monster must be destroyed, it's usually safe to assume that it doesn't have to be exactly 1 as long as it is at least 1.