Is it true that there is no absolute morality?

[Mister Agenda]

If morality is merely a construct, then it is the same as choosing between chocolate and vanilla no matter how much law, police, or societal disapproval you put on the other side. 

1. Morality is merely a construct
2. Reasoning
3. Then it is the same as choosing between chocolate and vanilla

You're asserting that if morality is a construct, then it is the same as choosing between chocolate and vanilla. I assert that this is not true. You can put the ball back in my court with an adequate step 2. And 'it's so obvious!' would not be an example of that.

Houses are constructs, but choosing between a shack and a mansion is not the same as choosing between chocolate and vanilla. Because I couldn't resist the allure of Step 2.