Personally I'd find it far far more creepy to bow to a political symbol than to a photo (especially in the context of a martial art where we are constantly bowing to other humans in a mutually respectful but totally non-worshiping way). I would not be comfortable bowing to a flag at all. YMMV.
I have been interested to observe a muslim practitioner in a dojo who stated up front that he had problems bowing to other people, and exemptions were granted. While I respect his religious views, I have thought on occasion that he applies them slightly variably himself, and I have a strong suspicion takes advantage occasionally of the "exemption" he has. It's a difficult area.
My own line of teaching leads to Inaba sensei of the Meiji Jingu Shiseikan - he is devout in his Shinto beliefs and explains them as the basis of his Budo - and yet he also challenges others to find the equivalent for their culture and religious beliefs - he is not seeking to convert people to Shinto.
In Japanese Budo, there are plenty of people that tend to be (or at least aspire to be) "more Japanese than the Japanese" - a position which I find entertaining at times
I remember visiting a dojo in the USA where the (caucasian) teacher seemed to be speaking (almost grunting) pidgin Japanese but with a Scottish accent (I grew up and went to university in Scotland) - his aikido was fine but I did find the scenario a little bizarre!
My own personal predilections are to seek to separate where possible the Japanese cultural baggage from the core truths - not an easy task, and the risk is to throw baby out with bathwater - but life is full of risks
Interestingly the more experience I gain, the more I realise how careful you need to be in distinguishing what is valuable, and what is baggage - and yet in a way the more I realise the value of basic respect for others - it costs nothing to be polite and act as a gentleman (showing my age and gender...).