A simple Google search shows that the referendum passed with 57% of the voters support, so that leaves us with a 43% who thinks it's a bad idea for one reason or another. Since around 5% of Switzerland is muslim, one could argue building minarets is not such a scandalous idea for Swiss voters.
OP seems to be suggesting that people should "do as the romans do", and I said while I agree with the general idea, his suggestion doesn't fit the case in hand.
In this case half of romans are verifiably not bothered [1] by the act of building minarets, then this simple act doesn't signal that people "go there without a degree of humility and willingness to adapt", in his words.
Or you could turn it around and say, if (having ability to) building minarets was such an unacceptable expectation to a point of painting one as a colonist, it wouldn't gather the support it gathered from the local community in the first place.
[1] to the extent of participating in a political process to explicitly disagree with the ban.
The University of Lucerne ran a study and came to the conclusion that there are around 20-30 women in all of Switzerland who wear a niqap or a burqa.
I would take the view that banning the form of your religious buildings (and implicitly, to your comment, being hostile to Muslims who in your response you seem to equate with a culture that destroys the possibility of liberty) seems more of a betrayal of the principle of liberty and freedom for all than allowing different people to pray and associate as they wish, providing they follow basic tenants of human law (not harming people etc).
Going back to GP's point, the deeper issue is that people thought this was worth writing in the constitution. Other countries apply such laws in different ways, so I don't think the Swiss direct democracy is to blame here.