I watched this recent video by Dogen about how immigrants should adapt to Japanese life etc.:
https://www.youtube.com/watch?v=9_tXp5sFlHQ
One of the things I found odd was that he mentioned “eating while walking” as one of the offensive behaviors foreigners should stop doing. Many of the other examples made sense to me, but for this one - I never thought this was “rude”, rather “odd”. Thinking about it, I had a few conversations about this over time, but never got negative vibes for it (at least directly). Might be that people don’t want to tell me it’s rude, but I also got no negative opinions about it from people who lived abroad for a while (and thus are maybe better at communicating with foreigners) and/or are usually more upfront with me.
So my current understanding: It’s odd but not rude. Thankful for any further insights.
You definitely get stares when you do, but as a tourist it’s hard to know exactly how one sticks out from moment to moment.
But, in a communally minded culture, what that man did was to recognise you as breaking the norm, and even telling you that what you did is near unheard of in their culture.
That’s akin to you being indecent, although harmless, in public; like a naked toddler running around in a park (in my culture at least). And the man was (mildly) telling you off, in a respectful and cirsumspect manner as to let you save face.