In Moslem countries, there is a death penalty for converting to Christianity (or any other faith, including some we would name Moslem as well), and likewise for preaching Christianity to a Moslem. So the moment they start going d-t-d, the ones so doing would be killed or if lucky violently chased from town and country. And the ones preached to, would be treated by others with a high degree of suspicion. Some years ago, a couple of lines in a KM warned JWs against sending literature or tracts to random addresses in Turkey, because this was creating problems for the ones receiving them. Likewise, in some countries, JWs on holiday are asked NOT to try to visit lokal JWs, because this draws the attention of others to that visit and to those local people, and creates problems for them.
I have some Arab friends, and they were witnessed to because they already belonged to Christendom, and so what they did or did not do, was of no interest to the authorities. They told me, the only possibility for someone wanting to change from Islam to Christendom/-ity is to move to Lebanon, because that is a liberal country.
So I don't think it is about being cowardly, it is about trying to keep people alive when surrounded by bloodthirsty people. No matter what part of Christendom/-ity, they find it as close as you can get to impossible to preach to a Moslem. You have to be veeery careful, hence the careful wording of the WT brochures.