Insulating the tools isn't really the issue. There's already a fair amount of insulation between me (the tool operator) and the business end of the tool.
The problem is, we're cutting through and crushing various bits of the car that weren't really designed to be indiscriminately cut into (which is why training is so important).
Both rescuers and victims have been seriously injured and killed when extrication activities turned potential energy stored in the car into kinetic energy. Air bag deployment systems, seat belt pretensioners, even the little hydraulic tubes that hold your trunk open and be extremely dangerous if their energy is released in an uncontrolled way.
So you can understand why we're a little leery of 85 kWh of potential energy sitting under the car...
Here's an example of airbags being deployed when the SRS controller was crushed with a hydraulic spreading tool.
Yeah, but we've had almost a century of experience dealing with that...
The issues involved are also very different. A tank of gas is actually a very stable thing. Barring a puncture, there's not much you can do to a gas tank to make it do bad things.
Cutting a gas line is no major concern. Shorting a high voltage/high current power line to the frame of the vehicle is putting a lot of trust in the batteries failsafes (that trust is almost certainly justified, but with a track record measured in years, not decades, you'll forgive us for being a little paranoid...).
As far as I can tell, unless people have done something stupid, your worst worry is not the shock from the batteries. The batteries are a variety of potential difference spread over a large area and will go on fire rather then discharge everything at once, which is an issue, but they will not explode with their total chemical potential, not even close. It is any big fat capacitors that you have to worry about. Now they are not storing anywhere near the capacity of the battery, but they can let it out with very low internal resistance and after heavy braking are likely to be fully charged. So it is a current that can be easily discharged, but you have to know it is there.
edit - I said it earlier somewhere else, but EMT gloves with built in glowy multimeters might be a really good plan.
double edit - if you think this is a good plan, feel free to nick it.
A 40 liter petrol tank can't discharge 85kWh of potential energy in seconds without ideal conditions (good vaporization or atomization combined with sufficient oxygen)
Neither can a battery. The internal resistance is too high. They can cook and go on fire a bit, but much less than a gasoline fire, but they cannot shock you with their entire capacity in a few seconds.
I would've assumed the production of specialised tools for electric cars would be a priority once they become popular.