Something everyone is missing a bit, you can download translation programs to run online, that will change whatever language to your own. Mind you, translation is difficult when you get into typos, literal translation and the grammar and meaning changing between them.

Neither Steam nor GOG actually does this, it's up to the app developers, GOG doesn't develop the games, and outside Valve titles, neither does Steam.

Because they're a bunch of fucking racists.

Because we're doing God's work in making English the world's only language! /sarcasm

I'd guess that because so many games sold by GOG are from the 80s, 90s, and early 2000s, when the world was a LOT less interconnected -- many developers didn't bother to even consider making localized versions of their games. And when they did bother to make localized versions, the work was sloppy and half-assed. This is why when I see comments like this:

I so completely agree 10000000000000%. I mean, translated menus and such can be OK, but games start feeling more and more different from the original language version the more they're translated because connotations, expressions, humor, tone, etc. are not always shared across languages. Especially when it gets to voice acting -- wow, I can't even describe how much I hate dubbing.

Wait, it's not about race, it's about language... so they must be... err.. linguists?

Look up "linguist" ^_^