Very uninformed question here: If customer protection laws don't apply because Steam is a free service... doesn't this render such laws irrelevant to software products? Could you tie any product to a free service that by itself just turns the subscriber's mouse cursor pink on Valentine's day?
Apparently, it doesn't matter if the service is actually used in any meaningful way (nominally a online content delivery service, physical medium 'bought' in a physical store).
Well, the issue is actually that software is generally not "purchased", so much as it is "leased". Much as a leased vehicle is not
actually yours, a piece of software isn't
actually yours. The software still belongs to the company, as your copy isn't a true
reproduction. The difference between a purchased piece of software and a free piece of software is minimal at best, as far as the binding nature of the EULA.
When I, personally, talk about how Steam is free- it isn't to make a difference, legally. It's to point out that, especially in Steam's case, you have no legal right. First Sale Doctrine and similar legal documents don't always apply in the case of intellectual property, or in the way that a software is transferred; however, in the specific case of Steam- you did not purchase it, and as a result it is easier for most people to understand that since it is not purchased, you don't have any rights to it.
In fact, you likely don't
own any of the software on your computer; and as such, you likely don't have any rights to the software. While I disagree with the practice of hindering the right to transfer the contractual owner of a piece of software, doing so is entirely legal. After all, if the contract for a leased vehicle is that you may not rent that vehicle to other people or groups for profit; you can't.
A lot of people make the mistake of comparing software purchases to physical purchases. The only time this comparison was relevant was when copy-protection was based on who had the CD. While some companies (Stardock) disregard copy protection, claiming that thieves and pirates likely wouldn't have purchased the game anyways; most companies take a more active interest in protecting their investments.
So, to answer your question... it's not that Steam is free that makes the difference. It's that the software is owned by the publisher- and therefor, the grievance for not being able to play it without Steam lies with the
owner (Firaxis), not with the
borrower (Consumer). As the borrower, you don't actually have many rights in regards to a licensed software.
I'm not saying that this practice is perfect, and I'm not defending the system. This is just the way it works, currently, under many legal systems.