There is Steam support on any distro, not by the distro community, but by Valve itself.
Steam has been packaged for most distros, however, there is a difference, some distros package it a bit more carefully than Canonical. The Steam client is basically an old firefox version that has been mutilated to serve Steam's purpose. The problem with that is that the mozilla trusted CA list can be accessed by the Steam client, as it basically uses the same one as the standard firefox browser. Now there is nothing wrong with the Mozilla trusted CA list as such, but there is if the Steam client can access it, because at that point, with every Steam client update, Valve can push it's own trusted CA list to your browser, which is probably not such a good idea. Second problem is that the Steam client can access your bookmarks and preferences in your firefox browser. It can access your trusted CA list and data in chrome/chromium too, but you can't edit that list, so you don't even see it there, but chrome/chromium is not a recommended application on linux, because it uses a lot of hacked up dependencies that may screw up your system, Google never uses anything standard, they package a lot of hacked up dependencies with their browser that shouldn't be messed with, because they are "normal" system dependencies, and Google does incorporate a lot of Java snippets in everything for no apparent reason at all, that's why distros with high security awareness refuse to provide Chromium/chrome in the official repos. What security aware distros also do, is package the Steam client with things like a strict SELinux profile, to block access of the Steam client to the rest of the system, and to package it with the p11kit, which deactivates the trusted CA list access and use of the Steam client, and diverts all trusted CA list queries to the system list, which cannot be modified by applications that run in userland. This dramatically increases the security and privacy of the Steam client. Canonical doesn't do that, just like they let Google push an unverified chrome/chromium version onto the Ubuntu repos, they also let Valve push an unverified Steam client onto the Ubuntu repos. This kind of "support" for third party spyware (also all of the third party "lenses" that send your search and system data, and your browser bookmarks and history, to all kinds of corporations) has earned Mark Shuttleworth, the CEO of Canonical, the Austrian "Big Brother" Award 2013:
http://www.heise.de/open/meldung/Big-Brother-Award-Austria-fuer-Mark-Shuttleworth-2034943.html
Bottom line is that Ubuntu is not such a nice distro, even though Ubuntu Core is occasionally very good (13.10 is actually very fast, too bad it doesn't have any support for the next standard display server in linux, that will knock the further Ubuntu development back enormously when they will have to support Wayland because otherwise Ubuntu won't run well or at all on Intel machines), because it doesn't support a lot of "essential" security features, and doesn't package with care, and their DE, Unity, sucks balls because it's an unnecessary clickfest like Windows, and their next-gen display server, Mir, is not supported by Intel, which is not nice of Intel, in fact it's pretty evil of them (that seems to be the general direction Intel is moving towards in general), but also a big problem.
Mark Shuttleworth has a Bill Gates complex, he's always set for himself the mission to beat Microsoft Windows, and has invested an obscene amount of money in 10 years of Canonical to try to achieve that. Now he wants his money back, and he has adopted a lot of cuttroath tactics from Microsoft. Canonical has severed the communication lines with the community (literally, they have taken the community inbox offline), and has chosen a purely commercial direction. Canonical has stopped funding the Ubuntu spins based on other DE's than Unity (Kubuntu, Xubuntu, Lubuntu), and they have gone their own way and are purely community based, and generally, since the breakup with Canonical, have proven to deliver a higher quality product than Canonical's Ubuntu with Unity. And that's OK for Canonical to do, but linux users don't have to put up with that, and that's why Mint is becoming so popular, why Kubuntu, Xubuntu, Lubuntu, Elementary, Zorin, etc... are becoming more popular Ubuntu Core-based distros than Ubuntu itself, and also why distros like Manjaro have become so popular in such a small timespan. Mark Shuttleworth thinks that because Ubuntu is aimed at beginning linux users, he can get away with it all, but that's not the case, there is always an open source alternative. Canonical started out with a similar business concept as RedHat and Novell, and although they did get to a point where they actually had a chance to break through in the enterprise services business, with governments, educational institutions and some services industries making contracts with Canonical a few years ago, they couldn't deliver the same amount of super high quality services that RedHat and Novell are known for. So users started to fork their own distros from Ubuntu Core or Debian and maintain it themselves, or switched to RHEL or SuSEEE, and Canonical lost a lot of contracts. That made Canonical change its business strategy, and go for the hipster model, with pointless marketing campaigns like the Ubuntu phone and the Steam support, and by allowing commercial spyware onto their distro like from Amazon, Facebook, LinkedIn, Google, Microsoft, etc... It's not like they had to implement the spyware to offer functionality to their users, Gnome or KDE integrate Google, Microsoft etc.. cloud services into their groupware and desktop software, but they do it securily, and they offer better functionality and integration at the same time, and they do it themselves, they don't have Google employees working on their code like Canonical.