Earlier quoted context omitted.
The insurance firm isn't exploitative. The patent troll is actively harmfully attacking people. The insurance firm (assuming they aren't secretly creating demand for their product) is mitigating the damage. Locksmiths and firefighters aren't exploitative.
Insurance doesn't mitigate damage, it amortizes it (typically across a group of entities). The expected average annual claims on an insurer's policies need to be lower than the sum of the premiums or the insurer loses money. This is why people in high risk categories pay more for insurance (eg young people and people with high performance cars have higher car insurance premiums because statistically they crash more o…
In this case it does because someone with insurance is a poor target for patent trolls. Assuming it becomes common you get 'herd immunity' as patent trolls become less effective which also lowers the cost of the insurance.