I'll bite -- I like puzzles.
Possibility #1
By analogy to genetics, each meme is in a struggle to survive against other
competing memes. One of the ways a meme is successful is by infecting large
numbers of people. As such it "should" try to infect everyone that it can
and the hands off approach implied by "live and let live" is at odds with
this struggle to survive.
Possibility #2
Live and let live suggests tolerance which suggests that what is true for
one may not be true for another. That truth is subjective. This is at odds
with the (implicit?) Virian belief in one objective truth that is true for
all people.
Personally I think "live and let live" is a cardinal virtue and I think both
my guesses contain fallacies. But I don't want to start bashing straw men so
I'll await to hear Richard's reasoning (or other possibilities).
Deron
(Another possibility - Because Church of Virus has dominion over the the
truth and anyone who is opposed must suffer the consequences. :-)