I'm sorry, but I agree with most of what you said and so am mystified about why you are taking me to task about it.

In standard English usage, if we are speaking of Cromwell and I say "The English massacred the Irish" there is no connotation that all English people took part in it or approved or that Cromwell's policies in Ireland are enthusiastically endorsed by today's English people. If you were to object and insist that I say "The New Army massacred the Irish, the Levelers and cavaliers had nothing to do with it", you'd be asking me to import an excuse into a simple statement of fact.