Complex sentence: Advocates are often normal users who devote their spare time to advocacy of their operating system of choice; many have a deep and abiding interest in the use, design and construction of operating systems and an emotional investment in their favourite operating system.
Split into simpler sentences: Advocates are often normal users who devote their spare time to advocacy of their operating system of choice. Many have a deep and abiding interest in the use, design and construction of operating systems and an emotional investment in their favourite operating system.