I wasn't involved in the original ruling but as far as "grossly offensive" is concerned, it certainly isn't.
Grossly Offensive
If you want to execute left-handed men named "Earl" in your country, that's fine. Don't go yammering about it in a Proposal. Yes, this includes screwing with a 'majority' group. Killing all whites is just as bad as killing all Jews. Or blacks. Or poor people. Things such as eliminating "all rights for $group", forced deportation of said group and the like fall under this too.
Arguing that there is a correlation between violence and developing nations may be somewhat offensive to some, but it does not reach the level of grossly offensive and it clearly wasn't an attempt to troll.