It's stealing. Rationalize it all you want by pretending it's not money they were getting anyway, or that you are instituting your own "try before you buy" policy, or that somehow taking data/information without paying is some kind of God-given right, but it's stealing.
My view is it's also stealing in when a company misrepresents it's product in terms of system requirements, features, or scope of product. Rationalize it all they want, they're still asking for my money to cover their costs. They're supposed to be selling an item of entertainment, if I don't find it entertaining, I won't buy it. If it doesn't work on my machine, I won't buy it. However, I also will not keep it on my machine for that long.
Besides, who's to say my religion isn't the kind that encourages the freedom of data/information? In that case, it is my god given right.
Here's how it goes in my scale.
If it's a single player game, I will check to see how well it runs. If it runs well and it's still a title that interests me (usually by going through tutorials or the first 'level' or such) I will remove the game from my system, to purchase it when I see it at a price point I find reasonable. They're still getting the sale if they've made a product I found worth it.
If it's a multiplayer game (or has multiplayer features), I will likely buy it outright once I see how well it runs on my system based to how many of my gamer friends have also purchased it, because if none of them did, then it wouldn't get played anyway and I'd have no need to buy it.
It's a fair system in my mind because if I were to purchase any other product (non IP speaking), I would have the right to return it based on my satisfaction of services. If I bought a TV (or other electronic device, or many other things) and it didn't quite live up to expectations, I'm free to return it and get my money back. That is not the case for most IP topics.
I can return a board game if it didn't live up to my expectations, I should also be able to return software under the same conditions. However, this isn't the reality we live in. The reality we live in is that software companies can do what they want and cry victim when they release shit product. Software companies know they have you by the balls once you unwrap that box. Your money's spent and it's over and done.
I no longer live under the ideal of "Well, they fooled me this time. I just won't buy their product next time." I feel my method is a bit better. I buy about the same amount of software as I did before (slightly less on average), I'm just happier with purchases now.