I don’t know why that would be. A wander through my local pet shop indicates that pretty much only non-electrical related products and lighting globes do not have instructions for use. In addition, ZooMed and Reptile One, for example, also provide instructions or product manuals on their websites for products of this nature. Easily checked out.
What your experience does reaffirm is the point I made earlier – that the experiences of any given individual should not be used as the basis of making generalisations. Relate them by all means, but do so in context, as you have done here.
Another point, from earlier posts - beware putting across hearsay as fact. Just because someone on the web said so in public does not make it fact. It depends on who that someone is and how they came in possession of the relevant information, as to how much credence it should be given. In this respect it invariably pays to be cynical rather than accepting and to therefore actively seek out independent and reliable verification before believing.
As Snowman pointed out, and very rightly so, it is important that we get the information correct on a forum such as this, in which many come to learn.
Blue