MrBernoulli ,you are not predantic,I was just stating that B says not to use reverse above idle.If idle was also dangerous it would've stated not to use it at all.
Due to the placement of the reversers on the engine it seems that idle reverse won't create much risk of FOD. Of course we won't use reversers on contaminated rwy's ,but if you use it when is dry snow you can see the effect of idle or above idle reverse.