Not as concise as I would put it so I will summarize.
They want to sell Anti-virus to Linux Users AND (more importantly) to Linux Servers that
handle Windows traffic.
It's easy with windows, they can sell their AV solution for the server, and a separate more
expensive server package that scans the hosts and traffic across the file server. Right now on
Linux all of this is being handled in user space with free open source programs that scan
specific server traffic like email of SMB traffic.
With the right kernel hooks they would have something they could create a product on and throw
their marketing weight behind. Without the hooks they are up against the question of "how is
this better the clamd?" With the hooks they can create a very invasive AV package, much like
the windows versions that hooks itself deep into the kernel, hurting performance with
negligible benefit but with the ability to claim that their package scans at the Kernel level
every file that passes through the Linux system. This would make it possible to sell Norton /
McAfee AV for Linux, and Norton / McAfee AV for Linux SMB. Without the hooks everyone can see
the negligible value, with the hooks it becomes much harder to compare because I think
everyone can admit there might be some situation where the Kernel Level hooks could grab
something the user space tool wouldn't be able to.