A Question for Ken Ham: Why not have sex with animals?

Ken Ham is mad at Miley Cyrus because she said this in an interview with Paper magazine:

I am literally open to every single thing that is consenting and doesn't involve an animal and everyone is of age. Everything that's legal, I'm down with. Yo, I'm down with any adult -- anyone over the age of 18 who is down to love me," she said. "I don't relate to being boy or girl, and I don't have to have my partner relate to boy or girl.

So Ken Ham's question for Miley is this: "Why not have sex with an animal?"

Of course Miley already answered the question by saying she was open to "every single thing that is consenting" -- and it's hard to get non-human animals to consent to sex.

But Ham's question is much more difficult for Bible believers, since according to the Bible God created animals to provide a "help meet" (spouse) for Adam.

And the LORD God said, It is not good that the man should be alone; I will make him an help meet for him. And out of the ground the LORD God formed every beast of the field, and every fowl of the air; and brought them unto Adam to see what he would call them: and whatsoever Adam called every living creature, that was the name thereof. And Adam gave names to all cattle, and to the fowl of the air, and to every beast of the field; but for Adam there was not found an help meet for him. Genesis 2:18-20

God's original plan for marriage was for Adam to select an animal for a "help meet."

It turned out (apparently to God's surprise and disappointment) that none of God's creatures had what it takes to satisfy Adam. So God had to come up with Plan B by creating a woman.

So my question to Ken Ham is this: Why not have sex with animals? Isn't that what God created them for?