The reason is that we are trying to do a little bit to combat the illegal copying of games. Legally bought copies usually have a manual with them, but WAREZ copies do not. We think it highly probable that illegal copying of the Might & Magic games contributed to 3DO's going belly-up, thus putting in jeopardy future games in this series that we like so much.
We do realise that some people buy these games quite legitimately without manuals, and we are sorry that we discommode them. However, we do hope you understand our position. We feel that we cannot stand by while illegal copying goes on and do absolutely nothing.
Are you sure that you don't have the manuals on your CD-Rom? See if you can find a file named something like manual.pdf