> Whether or not they do doesn't really disproportionately harm a minority group.
It does disproportionately harm a minority group of porn afficionados. If your point is that LGBT minority group has some rights that porn afficionados minority group does not have, you'd need to prove it.
> One actively targets a minority group.
The search results will equally be hidden from heterosexuals and homosexuals alike. It's not that Amazon is treating LGBT group in a different way — all the population is targeted the same.
Well, no... I don't give a shit if Amazon sells porn. Whether or not they do doesn't really disproportionately harm a minority group.
> what are these differences?
One actively targets a minority group.