Yes, definitely. There is a disturbing trend of faux-SJWs opposing interracial marriage or "considering" the possibility that it's OK to oppose interracial marriage for faux-SJW reasons. It's terrible.
With specific, small ethnoreligious groups, I'd say it's OK to oppose it on a personal level (e.g. "I wouldn't want to marry a non-Faroese person"), but getting involved in other people's personal lives is not cool.
Serious question though: What negative effects occur to people who come from mixed Jewish/non-Jewish marriages? Like I said, serious question, I've met such people in the past and never noticed any issues they had that could be related to that.
I think the main issue is that Judaism is traditionally matrilineal (although some modern Jewish groups are more lax on this rule) so a Jewish man would have to marry a Jewish woman in order to have Jewish children.
Personally, I don't think I'd go out of my way to marry another Jew, but if I was considering dating a particular person I might consider it to be a "positive" thing if they were Jewish. I wouldn't really see it as a "negative" if someone wasn't Jewish, though, as long as they're OK with me continuing to be a vaguely Jewish agnostic.
