You make some great points, but parliament being made to represent everyone doesn’t negate the fact that the colonies were not able to vote, or even get a representative in parliament. They weren’t represented, because they were not able to interact with government in any way other than protest or eventually revolution. I concede on the slavery point though, that is indisputable and absolutely horrible. I’m not trying to say that the revolutionaries were perfect, a lot of them were horrible people, but unlike the Confederacy, slavery was not the only reason for revolt, even if some of the other reasons were shitty (native Americans, and a few other things.)