being ‘technically’ Jewish; questions about gatekeeping

Hi, an incident has been troubling me. For context, I’m Jewish (matrilineal) and baal teshuva after a lackadaisically religious upbringing. Sorry if this is looong and thanks ahead to all who read.

I socialize in a lot of artsy / creative circles and people are, like, really into Kabbalah iconography. I think it represents some kind of interesting esotericism to them, and I think it’s sort of whack but generally I just avoid those conversations and artworks by non~Jews which include Kaballistic or other Jewish snippets pretty randomly.

Lately an acquaintance released an artwork combining Kabbalah symbols and Hebrew applied to pagan shrines / objects, which were also mixed in with Christian symbols and concepts. I mentioned to him that this feels weird to see because Judaism, idolatry and Christianity don’t mix well. He was upset and said that despite being raised Christian and currently identifying as an atheist, he also identifies as Jewish, though “not technically” ‐ at some point he discovered through ancestry research that a great‐grandfather in his family was Jewish, and he quickly became upset that I’m “questioning his culture” since this great~grandparent lived through the Holocaust.

I felt awkward at the idea of Jewishness by halacha or upbringing being a mere ‘technicality’, and the idea of the Holocaust being brought up as leverage in this context, so I told him bluntly he’s in no way Jewish based on this family relation, and it doesn’t entitle him to authorize avodah zara. Then I chilled out a bit lol and mentioned it’s cool to explore one’s family heritage and that if he becomes interested in learning more about Judaism, maybe take a look at the Noahide community or something like that.

Long story short this was really upsetting to him and he felt I was gatekeeping Judaism and that I wasn’t following Jewish values by being judgemental. I feel guilty and conflicted; while I tried to be positive and nice in my interaction, I did flat out deny that he’s entitled to identify as Jewish “non‐technically”. I’m not a religious authority, and it wouldn’t have cost me anything to hold my tongue instead of making someone feel embarrassed. At the same time, I just feel really ill at ease lately; half of the people I meet are directly antisemitic and the other half promote some type of new age Judaism which claims to be positive toward Jewish people but often feels just wrong somehow.

I’d love to hear some ideas from the broader community about all of this, how you perceive this kind of new age / ‘inclusive Judaism’? How much (if at all) you would speak up about this kind of thing, and how to go about it more kindly (if at all)? I’d like to do better next time if I did badly now.

Thanks so much (: