Yes, Swedish has false friends not only with English but with German too. In fact, snäll was often used in the same sense as schnell up until the 18th century.
The original meaning of this word in Old Swedish was able, capable, good, and from there on it branched out. Today it only means kind though, except as gramphos says, the other sense survived in the word snälltåg.
It seems a bit of a trap question ... I can picture a fast horse, I'm not sure what a kind horse does though. Makes me breakfast in the morning? Remembers everyone's birthdays?
Incidentally, 'snell' is defined as 'smart, quick, able, bold' in old English. It's an extinct word now though...
Thanks for sharing this. You're right we wrote this sentence because of a Swedish meme. The thing about this meme is that it uses some really horrible spelling, like small children will spell when they first start to write, so learners: be warned. But for instance snel hest gå på fest äta kaka dricka lesk is something you can see (I guess the peak of the meme was several years ago. Here's a link to a site about it: http://www.bartoll.com/snelhest/).