Because the price you pay for an Icom 2720 will just as easily purchase a new Icom mobile with the proper certifications, proper specifications, and capabilities to do the job correctly.
I fully understand the limitations on volunteer fire fighters, but they are no different or no more special than any of the rest of us. Choosing to follow the rules or not is a conscious choice that each of us make. When human lives hang on the line, choosing between a properly designed radio and a hacked amateur radio, shouldn't be a tough one. It should be a no-brainer.
And yes, modern amateur gear is much cleaner than the older stuff, but each and every radio is different, and unless they have been put on a service monitor, there is no way to know if it is aligned properly for the frequencies outside of the designed area of operations. Blanket assumptions that "it's modern so it's OK" doesn't fly.
What ticks me off worse is that government, local, state or federal, take your pick, is spending billions on technology to solve interoperability issues that either do not exist, or could be solved cheaper and with more personnel training. If agencies were not being forced to spend outrageous amounts of money on overpriced radios that they don't need, maybe they could afford to outfit those that really need radios with the correct equipment.
It disappoints me to see a licensed amateur radio operator thumbing his nose at the rules. It disappoints me more to see someone who obviously has a need for a proper radio not having one due to government stupidity.