It's not an insult--it's actually a descriptive term in this context (albeit one with strong negative connotations).
If somebody wants to inform me, they had better say something like "claim 4 of the '387 patent is for accepting coins with a vending machine, which clearly is anticipated by the prior art".
Saying "oh noes, evil patent troll" does not inform me. It is sensationalism and gets flagged as the garbage it is.
Besides, the adjective 'patent troll' has very little to do with the veracity of individual patents. Patents can be perfectly sound, but still be subject to trolling. Trolling is generally the activity of treating patents as a stock portfolio of licensable monopolies, without an intention of undertaking the risk of actual production, and this seems to describe the majority (but not all) of the behavior of I.V. rather well.