But the proper argument would require much more examples, and much defining of what a Chesterton Fence is.

Indeed. Your examples seem to be simply changes. Not every change is a fence, and for that matter, not every taking down of a fence is done because no-one thought for five minutes about why it was there. All of those examples were intensively discussed at the time. Those opposed spoke at length about why it was there and why it should stay there, and those for spoke at length about why it should be taken down. In particular, extending the franchise, in the UK, was a process whose major part extended across nearly a century, step by step from the 1832 Reform Act to women getting equal voting rights in 1928.