Eating raw spinach is perfectly safe and very healthy for you actually.
Raw Spinach is considered a super food and can improve your health when eaten raw as well as eaten when spinach is cooked.
However raw spinach contains oxalic acid which can bind with calcium which makes it a problem for people who have kidney problems or kidney disease.
So if you have kidney problems or kidney disease then you may not want to eat raw spinach and only eat the spinach after cooking it.
Btu as long as you have good kidneys and no kidney problems then eating raw spinach as much as you want too is perfectly okay and safe.
I've eaten raw spinach for years myself and am pretty healthy as a result.
I love to eat spinach both raw and cooked and raw spinach also goes good in some salad such as spinach salad.