Cheapest way to get Indie Game: The Movie Special Edition

I feel like anything short of complete piracy is defensible

Yet, some devs have openly said they prefer people pirate their game instead of buying them from places like G2A.

I think any means of obtaining a legal copy of a game

Here is where one of many problems start: Resellers buy bundles (mainly good quality Humbles) and sell their games which is against Humble Bundles TOS. You are not allowed to resell them. And this is only one of the harmless type of resellers... There's shady people with stolen credit cards, hackers, scammers... Even Youtubers and other media guys that get free keys and just sell them for more extra cash.

Everyone needs to know if they are acting good or not, if their impact is making the world better or not.. I'm not forcing anyone but I personally avoid this site (and other NOT LEGIT sellers) to death.. Just because you don't have a job doesn't mean you need to support that crap. There's a lot of other things you can do without money. I'd like to have a VR headset but don't have the money, so am I stealing it somewhere or paying someone 1/10 of its price who is stealing it for me? Guess you wouldn't do that either.

Oh and btw browse the forums here, a lot of people complained about revoked games recently, in most of the cases it had to do with that marketplace ;)

I feel like anything short of complete piracy is defensible.

There's an argument to be made that it is actually more morally defensible to pirate a game rather than obtain it through G2A. The developer of Defender's Quest argued for this by way of the "Four currencies model", a model which expands upon financial cost to add a psychological cost (the four currencies are: Money-dollars, Time-dollars, Pain-in-the-butt-dollars, Integrity-dollars). He argues that the moral cost to obtaining the game through G2A outweighs the cost of pirating it, because the true cost of G2A is far more harmful than one would assume.

but at least OP and the people who go to G2A aren't just outright stealing the game

You have no idea if or if not you are outright stealing the game, mate. Only if you know the source of the key can you know if it's something somebody bought, or something that was stolen in some way or another. It's a lot like "cheap" bicycles, "cheap" televisions, etc. Long before you were born, there used to be a website where people could "pay" really cheap prices for MP3s -- a shame they were all pirated, and the "customers" were paying the pirates to let them pirate along.