Let's try to move away from the more personal comments and back to the original point.
I think you could make a similar argument for about half the figures we see posted here. From Nazis to crusaders to Romans and on and on, there are lots of topics that come with some pretty dark historical baggage. Okay, this is an individual, but so are figures of Hitler or even Alexander the Great. Alexander razed the city of Thebes and slaughtered or sold all of the inhabitants into slavery. His story gets a little more brutal once he gets to India. But I don't think we like these figures and paint them to celebrate their bad deeds. It's because we're interested in their and our own history.
Do I think this hobby needs a line of figures of famous murderers? No. But Jack the Ripper is part of our popular culture. According to Wikipedia, the source of mostly accurate information, "The Ripper appears in novels, short stories, poems, comic books, games, songs, plays, operas, television programmes and films." My friends even have a board game called Mr Jack. If it makes you feel any better, Jack the Ripper tends to lose. There are numerous works, including that game, that have combined the world of Jack the Ripper with Sherlock Holmes. I'd like to think the recent Jack the Ripper figure release is more about this fictionalized version rather than the actual man. I think that view makes even more sense considering the recent release of a Sherlock Holmes figure from the same manufacturer.