He went to an LGBT restaurant. That's not anti-safeguarding. To suggest it is, is purely homophobic.
I have to say it's probably not the most politically neutral act though, and isn't terribly diplomatic given the political culture in Poland ATM.
Having said that, being anti-homophobic has broad consensus within the UK so isn't politically sensitive on a domestic level.
The Polish embassy is unlikely to put in a complaint anytime soon due to the situation with Ukraine though.
It's probably making a point that's fair in terms of British cultural values and isn't going to upset too many here though.
I really don't see what your problem is her OP other than to try and do a forced team bullshit homophobic crap that William must be bad like others in the family because he went to a LGBT restaurant. Really? Can't you do better than that?