There is no good reason to make any assumption other than to assume that the rules are confined to the language used in the OP and nothing else. Extrapolating something that isn't there is dumb.
From an outside point of view, OP 'obviously' counts as a poster and there was nothing that would indicate otherwise.
Another example of a bad assumption is to assume that a contest in which 'free' (definitely not the case here, this is a skills-based contest) money is awarded to the winner should never elicit arguments from participants questioning the clarity of the rules.
It's not bitching, or moaning, or selfishness, or anything of the sort. The only reason people assume that it's bitching is because of the amount of BTC involved and because they think that not arguing about it somehow makes them a better person or cooler or more 'mature.'
Make the game clear, or don't (not specifically directed to the OP, but to contest-holders in general). But if you don't, don't be surprised when people call you out on your lack of clarity, especially if they have a stake in your game.
I call it bitching because if you notice, everyone does it AFTER THE FACT. As in they don't ask the question, just bring it up when it doesn't suite them. If you really wanted to know why not ask a question before you post? Also I already sated what you need to do if you think I am being 'too unclear' in this post which I have in bold for anyone confused. If you are still confused after these posts I am afraid I cannot help you.
This is a free bitcoin because any time you spend trying to win it is equaled by the time I have to moderate and determine a winner. People don't get paid for time here, this is mean to be something fun. If you don't agree with anything I do? Don't participate. You say, too bad expect people to complain anyways? I call that bitching. I have a feeling my banned list is going to be rather long on this site.
If you think it's unfair because I did not do something you thought I would and didn't state it, again don't play my giveaways.
If you feel uncomfortable not knowing the rules about one of my giveaways, don't participate.
Surely you can't still be confused after those statements.