Rhiannon,
The huge amount of peat (to a great depth) suggests very heavy aforestation - maybe that's why.
As for PeteH finding it scary, there are numerous instances of people finding upland areas scary in the last two or three centuries. Perhaps the proximity to the clouds, and the threat of very bad weather closing in without warning are reasons.
I've come across quite a few people on the hills in Cumbria who have also been scared and out of their depth. Most aren't used to it, and find the proximity of extreme weather to be frightening. Perhaps that's why our ancestors shied away from it, although that isn't the case elsewhere.
Maybe the evidence is buried under the peat.
Just a few thoughts,
Regards,
TE.