Until 1935 you didn’t need a driving test in Britain. Until 1967 there was no drink-driving limit, until 1983 no safety-belt law. Until the 1960s you could put up a sign saying “NO BLACKS NO IRISH”. Convicts could be birched till 1962; schoolchildren caned quite recently (it was in South Africa that enraged nuns would lay about me with a ruler, rosaries rattling, but contemporaries in the UK report the same). You could blow smoke in people’s faces in a pub or office till 2006. Thus the borders of what is acceptable and legal in any civilisation naturally change.
They do not always contract: we now have same-sex marriage, and a historically unprecedented range of personal rights. But new things happen (such as mass immigration)