An important part of being an outlaw is managing public relations. If everyone hates us, then we are deeply screwed and likely would be even if we clear our name. If we make sure only the people already actively against us hate us, we have fewer people coming to actively kill us a much rosier outlook in the long term as well.
Which is to say we want to be very careful about burning every possible bridge just because we're an outlaw. We want to prove our innocence and stop being an outlaw at some point, after all. Doesn't mean we can't insult people, necessarily, but we should sure be pretty selective about who and how.