The example of one person who has had no contact with others and goes to a second home in the middle of nowhere, doesn’t really have relevance (except to that one person) in terms of the current restrictions, because it applies to very, very few.
Most second homes are in communities and travel between them involves the mixing of communities and the spread of the virus. As I said previously there are over half a million people who register more than one address which is potentially a large amount of traffic on the roads and within communities.
Leaving aside the virus, the “right” of an individual to own two dwellings often impacts on the rights of those in the “holiday home” community to family life, shelter and work. Before these places became “second home’ locations they were villages and towns where people carried out ordinary lives, bought homes, raised families, used shops, worked, supported each other. That has been denied them.
This is what I mean by one persons rights denying those of others.