下面才是逻辑！
slippery slope argument:
同性恋合法了 --〉 兄妹恋，父女恋，人兽恋 也会合法。
Pattern:
If we allow A to happen, then Z will eventually happen too, therefore A
should not happen.
Explanation: The problem with this reasoning is that it avoids engaging with
the issue at hand, and instead shifts attention to extreme hypotheticals.
Because no proof is presented to show that such extreme hypotheticals will
in fact occur, this fallacy has the form of an appeal to emotion fallacy by
leveraging fear. In effect the argument at hand is unfairly tainted by
unsubstantiated conjecture.
Example: Colin Closet asserts that if we allow same-sex couples to marry,
then the next thing we know we'll be allowing people to marry their parents,
their cars and even monkeys.
