Hmm. I see your point about being respectful, and it is a good one. As a general concept, I will toast to that. When in Brussels, I dress more nicely than I would for similar functions in the US. Even west coast to east coast of the US has a difference in formality, and I try to dress up or down as expected. It is simply easier on those around me.
And yet, I am not ready to imagine that holding hands in public should be seen as disrespectful. Rather, in the non-Portuguese countries where the men were beaten – perhaps we could spare a moment to reflect upon how disrespectful that reaction is?
It takes some courage to change norms. As forms of civil protest go, being young and openly in love seems a relatively delightful way to nudge equality forward.
But I do see how attempting to change a society that is not originally your own clashes with the notion of being a good guest. There can be multiple values in play.
In any case, it is beautiful to see Lisbon is not a place of violence and hate. Unsurprising, but beautiful.