In countries that are signatories to the ECHR (European Convention on Human Rights) it is _sacred_, given it enshrines a right to privacy in Article 8 for some 800 million people. The Court is pretty judicially active in enforcing the rule as well, even in member states that have governments with crappy human rights records like Russia.

America and a few others are arguably outliers in the western world for failing to recognize privacy, and the right to private family life, as a fundamental right in some form of constitutional legislation.

What if you found out today that your neighbors have been watching you undress for the past year? In material terms, nothing has changed and there is no material harm to you, but knowledge of that level of intrusive exposure without consent is something most people object to.

I genuinely don't really care about things like this. I mean sure It'd be a little odd if my neighbour would stare at me but I generally don't mind, as you said no harm done