Acceptable??

I was thinking about the things considered taboo were back then practiced... for example: polygamy and paedophilia or what it was called pedestry

Many people or should I say activists bring the past to justify their actions... So my question is are they right to use what in their context was acceptable back then... in today's society?

No, just because something was seen as acceptable in the past does not mean it gives people the power to do it now. If people could do that and get away with it, then you would have everyone who is convicted of paedophilia using the past as an excuse. There is a reason things such as polygamy and paedophilia are not tolerated now and that should not be changed let alone accepted.

We should for the most part be horrified by what was acceptable in the past. I mean the obvious ones of slavery, women not being able to vote, religious persucution etc.

One thing that is interesting about the idea of looking back at the social problems of even a few decades ago is that most educated people can laugh at the obvious fault that was there then, say with the gay rights issues of a few decades ago [at least in Britain] and congratulate ourselves on how far we have come.

Thing is, in 20 years time we will be doing the same thing for the current issues, say teaching creationist theory in schools without evolutionary theory....well I hope we will be laughing at how backward we almost went.

It was once acceptable to be racist, own slaves and beat your wife, definetely not acceptable today. People evolve (hopefully)

Anyone can use anything to argue a point, but just because they can find examples of when such things took place does not mean it is acceptable behaviour, obviously things change for a reason.