Hi, John. I don't think that you should be scared of using a blowtorch to remove the paint, but your contractor should be. With a 120 year old house, it doubtless has lead based paint. Getting this paint too hot will cause the lead to vaporize and the fumes are toxic.
A heat gun is a much more controllable way to remove the paint. It, too, melts the paint but since it is working at a lower temperature. the risk of the lead vaporizing is much lower. Heat has been used for many years so fire should not be a concern with an experienced contractor using either method. But certainly he should have a good source of water around before he starts, just in case.
A much safer method is a chemical stripper but they are slow where you have multiple layers of paint. High pressure water can also be used but it does tend to attack any areas of weakness in your siding boards and leave it rougher than the other methods.