LCMS "vs" ELCA Confessional Lutherans re: Catholicism

In my personal experience as well as my theological research, I've generally found that among confessional Lutherans (i.e. those who accept the Book of Concord), LCMSers tend (there are plenty of exceptions, of course) to be more aggressive toward (Roman) Catholicism, and I'm really not sure why that is. It's not that they're anymore "really Lutheran", because as I noted, there are ELCAers who confess the BOC just as fervently. The latter tend to be more interested in figuring out exactly why we Catholics do and believe the things we do, while the former seem to prefer the polemical style of judging from afar (again, these are general tendencies, not across the board stereotypes). This is in no way to question the theological acumen of either camp, nor their good will... it's simply something I've observed.

So what's the deal, guys?