"It's surprisingly hard to come up with a balanced version of such rules."
Unless you're satisfied that the occasional "false positive" is an acceptable side effect. Sure, a "no swastika tattoos in my house" rule _might_ mean I (or the OP) end up not becoming friends with an edge-case - and that might be sad, but if the flipside is having to go to a lot of extra effort to find some more specific way of screening the neo-nazis who outnumber the edge-cases 1000:1, maybe that's a choice I'd reluctantly make.
Sorry strange-religion-guy and artisticly-dubious-gamer-dude - you might just end up "collateral damage" in my fight to simplify my life.
OK, so Hindu isn't that "strange", but I tend to doubt very many Hindus have swastika tattoos without also falling into the "strange-religion-guy" circle on the Venn diagram...
(But I also fail because of the "not every neo-nazi has a swastika tattoo either" thing...)
Actually, the swastika is used to bless things in Hinduism. When my parents bought a car, they put a swastika on it while the priest prayed over it. I had to point out that they might want to move that indoors somewhere before they got reported to the police by someone who didn't know what they were looking at (when the Nazi's stole the symbol, they mirrored it).
Generally speaking, though, dealing with things on a case-by-case basis is the appropriate and intelligent process. You're perfectly capable of analyzing a visitor's swastika tattoo within its own context, and determine whether that particular individual is, in fact, someone you're willing to allow into your house, without having to apply a hard-and-fast a priori rule.
Unfortunately, as the Reddit post describes, dealing with case-by-case analysis of pornographic material posted to reddit was simply consuming too much time and attention from the admins. They could either scale up their staff for dealing with grey-area cases, at the expense of other activities they might undertake to improve the site, or they could simply no longer permit grey-area material outside a certain boundary to be posted on the site. They chose to do the latter.
Unless you're satisfied that the occasional "false positive" is an acceptable side effect. Sure, a "no swastika tattoos in my house" rule _might_ mean I (or the OP) end up not becoming friends with an edge-case - and that might be sad, but if the flipside is having to go to a lot of extra effort to find some more specific way of screening the neo-nazis who outnumber the edge-cases 1000:1, maybe that's a choice I'd reluctantly make.
Sorry strange-religion-guy and artisticly-dubious-gamer-dude - you might just end up "collateral damage" in my fight to simplify my life.