The techniques are not identical. The use of the bow, and the types and use of ornamentation are not the same. Just as all traditional fiddling is not the same. Some styles are 'more' classical, some not. If anything, baroque music has more to offer than modern classical - but many violin teachers offer a one size fits all approach to their own music- students learning three pieces for an exam will be taught the same technique for all three, even if one is 18th, one 19th and one 20th century.

There are areas of overlap, but there are differences, and the main one is the technique used to give the music the right feel for the dance. Just listen to a classical player trying to play a jig.