"There's an issue about being overtly Jewish. People don't like Jews as much as they did," he says. "Effectively, you're putting a target up for people who feel Israel is being unnecessarily violent and aggressive. But, beyond that, what we've seen in Europe over the last year is, scratch the surface, and a lot of antisemitism ... is (still there), where we thought it might have gone away.
"This is my tenth Edinburgh [Fringe festival]. There's always fuss with the pro-Palestinian lobby here - they're very vocal - but last year... people were intimidated.The protest became like an Edinburgh show in itself," he says, recalling the protesters holding up pictures of dead babies, and chanting into megaphones: "Free, free Palestine! Killing babies is a crime!"
"I can't argue with that, but it's so much more complicated than that," he says.
During the conflict, a poster advertising his show, "Jewish Chronicles", had stickers put on his eyes and mouth. The symbolism struck him forcibly. "They're (Jews are) blind to what Israel is doing and they shouldn't be speaking" is how he analyses it.
"If you have issues with Israeli policy, the words Israel and Jewish are interchangeable. I wouldn't say it was antisemitic, but I was targeted."
In response, he wrote a song about the boycott for this year's show, but dropped it. "Not because I was chicken: I didn't want it to be all about Israel. I opted for ‘Jerusalem and Me’,” a song which covers his fraught relationship with Israel's capital.
As he puts it in the song: "Jerusalem, we've got a problem - we always have and we always will; here in the diaspora some day I may need you, if they come in for the kill."
He regards the Boycott, Divestment and Sanctions (BDS) campaign against Israel as "abhorrent" for its indiscriminate nature, but is not uncritical of his potential refuge. "Now, among Jews, I don't think there's such a blind acceptance of what Israel does. In 1967, the whole world loved Israel, and now the whole world doesn't love Israel. The small world of blind allegiance to Israel is going the same way as the immigrant, Yiddish-speaking world went before it."
Post-Gaza war, no one has sought to attack or even berate him - in one of the few times that happened, six years ago, a female audience member was offended by a line saying he felt "some shame at what was carried out by Israel in [his] name". It's more a niggling sense of uneasiness at having a show with "Jew" in the title in an atmosphere that is a bit less welcoming than a couple of years ago.
"It's in the language, with people saying the Jews are doing what the Nazis did - on social media, it's all there."
The post-Gaza war landscape bears the scars of the conflict, with a sense of calm replaced by apprehension. "The feeling of being ostracised for being Jewish or held responsible for the deaths of those Palestinians in Gaza, you could even call it the feeling of guilt, is more intense. It could be my internal world. It might be paranoia, but I don't think I'm alone in that. The way it looks, the finger gets pointed at you."
Yet being out there as a Jewishly-branded performer is laden with uncertainty. Although he sold out at the St James Theatre in the West End twice this year, he says: "I haven't had that much work in the UK, apart from shul and charity work. It's more difficult to get a gig, but I'm not quite sure why."
In a strongly sentimental set, in which he accompanies himself on the Yamalka - as he jestfully calls his electronic keyboard - he traces his Jewish journey from his ancestors' immigration from eastern Europe to his parents' divorce and his own marrying out, divorce, assimilation and Jewish "reawakening".
When he began, he had craved acceptance from other Jews. "I was terrified I'd be pilloried. I hadn't lived a Jewish life - why was I doing this at all?" Now he has been accepted, he says: "So, I'm OK with the Jews, and suddenly I'm in a world where it's not so easy to be overtly Jewish, and to make a song and dance about it. Somewhere in myself I feel uncomfortable about pictures of dead babies."
Having performed last autumn off-Broadway and in Los Angeles, he was struck by the more pro-Jewish and pro-Israel environment. Back home, he agonised over the show title. "I've still got this thing - it's too Jewish, too Jewish. I was going to call it "Too Jewish?"
Nonetheless, having his work endorsed has been "very gratifying". And yet, he adds: "It doesn't mean I am not neurotic and insecure, and being Jewish amplifies that somewhat - the oscillation between crippling self-doubt and supreme self-confidence."
Daniel Cainer: 21st Century Jew is at the Underbelly, Cowgate, at 1pm until August 30
