Can’t see the rest of your room but it seems like you probably need a bit of softening - maybe an area rug and some acoustic panels on the walls? Those old apartments didn’t really do party walls very well, so sounds transfer is always an issue. Adding some acoustic treatment will not only help with neighbours hearing your music but it will also improve the sound in your listening space.
The ironic thing is that most of these salespeople probably have fairly mediocre systems at home, because frankly, the pay for their job is not that great. So there’s probably some psychology at work there that’s rooted in their own inability to have a really nice high end system.