I think insurance companies make it a point to say no, in the hopes that customers will not argue their case, and they can save money.
A few years ago, meth-heads broke into my cabin and stole everything...and i mean everything. Took the food outa the cabinets even, blankets off the beds...if it could be carried they took it. Clothes, boots, gear, all gone. Generators, tools, all loaded into my utility trailer, which they drove off with.
They tried to steal my tractor & ended up frying some electrical stuff; fortunately they couldnt start it but they did fry out some of the gauges.
Same for the 4-wheeler...they hammered a screwdriver into the ignition & tried to force it to turn. no luck there either, they just managed to tear stuff up.
Insurance (State Farm) said no to claims on the tractor & 4 wheeler "because they are vehicles & need their own policy for coverage" and paid nothing.
Initially they didnt want to pay the claims on all my gear either...they asked for receipts to prove i had the stuff. I asked the guy on the phone if he had the receipt for the shoes he was wearing since the thieves stole several pair of hunting boots, and he stammered a bit and admitted he probably didnt.
After a month of that i called my agent of 25 years and reminded them i was paying State Farm for insurance on 5 vehicles, 2 businesses, and my home, and if they didnt get this handled i would cancel every policy before the next billing cycle. They did finally pay off, though it was about 30-40% less than what the stuff cost me to fix & replace.