I think I understand what you're trying to say -- that we shouldn't read too much into the mistake because comics make grammatical errors in foreign languages all the time, frequently with no connection to race -- but I'm not sure we can let them off the hook for that. IMO, many of those errors are xenophobic: not xenophobic as in the authors or editors consciously hate foreigners, but xenophobic as in they don't value doing the necessary cultural research and thus, implicitly devalue the other culture or perpetuate an insular worldview. ("Why should we bother looking up the correct conjugation for this Spanish verb? Who cares? It's not important.") But Xenophobia plays really easily into racism, as it does here.