The link doesn't work, though as the Telegraph is pay-per-view we wouldn't be able to read the article anyway. I guess you subscribe to the Telegraph myxpyr.
All the NT properties I visit are not only about the house and gardens but there is also information about the people who built them and lived there. Not long ago you would have found out nothing at a NT property about the people who worked in the house rather than those who owned it but now you almost always look in to the lives of the servants, things change. Though I wouldn't say any of it is 'rammed down my throat' not really the NTs style. If you've never looked at the history before then I'm sure you won't notice any difference. If you have been interested in the history but don't want it tainted by uncomfortable truth then that is something else entirely. Saying that someone made a vast amount of money from the slave trade to build a huge house isn't political correctness from a woke goon, it is just fact.
Why does that upset you so much?