I guess my question is: If I split the log and the grain is swirly then wont it just split directly into the snakey monster (...)?
Yes, it would, and that is exactly the reason WHY you want to split a log. If, just by chance, the log splits in a 180 degree twist, you'll immediately know you need to dump the log and use it for firewood. But if the log splits in a 45 degree twist, you can still use the wood by straightening the roughed out stave with heat or steam. A straightened, split stave will still follow the grain (whereas a sawn stave won't) which translates to the strongest possible wood.
In some situations, you can still decide to saw a log instead of splitting it. This could be the case if you will be backing the bow anyway, or if you will process the log to boards and/or laminations. Another possibility is if the log could yield two staves if sawn in half, but splitting might result in a run out, ending up in only one stave. Smallish logs (about 3" diameter) could be used for that. I've personally also sawn a yew log in half (as opposed to splitting) when I KNEW the grain was
slightly but not dramatically twisted. I didn't want to straighten the stave, so I chose to saw the stave straight, because I knew the slight twist (maybe 45 degrees) would not hurt the low drawweight and strong wood species. But this is risky business and requires a 'feel' for the wood - not something I would recommend a beginner.